A self-depreciating smile

Charles Dickens, Dombey and Son (1846-1848), chapter xxxvii 'More warnings than one' (first published in number xii of the serial, September 1847), page 554 in the Oxford World's Classics edition.
Edith suffered him to proceed. She looked at him now. As he bent forward, to be nearer, with the utmost show of delicacy and respect, and with his teeth persuasively arrayed, in a self-depreciating smile, she felt as if she could have struck him dead. 

I was listening to this passage on an audiobook and I assumed David Timson must have simply mispronounced the word "-pree-shee-ayte" instead of "-prek-ayte". However, there it is in the text: self-depreciating where one would expect self-deprecating. Of course I expected self-deprecating: depreciation is only what happens to assets for tax purposes.

The OED has the following. First the relevant extracts from the entry for self- :
self-, prefix1. Compounds in which self- is in the objective relation to the second element: a. With nouns of action.
self-deprecation n.
1924 W. HOLTBY Crowded Street xxxv. 260 Don't you think that this self-deprecation of yours was a little like cowardice? 1977 A. GIDDENS Stud. in Social & Polit. Theory ix. 307 Suicide represents an extreme on a range of possible forms of self-aggression, which extends from relatively minor forms such as verbal self- deprecation to actual self-destruction.
self-depreciation n.
1827 J. C. HARE & A. W. HARE Guesses at Truth (1873) 2nd Ser. 503 Self-depreciation is not humility.
Now the entry for the verb Dickens uses, with the quotations removed except one from Our Mutual Friend :
depreciate, v. Pronunciation: /dɪˈpriːʃɪeɪt/
Forms: Also depretiate.
Etymology: < Latin dēpretiāt- (-ciāt- ), participial stem of dēpretiāre (in medieval Latin commonly spelt dēpreciāre ), < DE- prefix 1a + pretium price. Compare modern French déprécier ( Dict. Acad. 1762).
1.
a.
trans. To lower in value, lessen the value of.
b. spec. To lower the price or market value of; to reduce the purchasing power of (money).
2. To lower in estimation; to represent as of less value; to underrate, undervalue, belittle.
1865 DICKENS Our Mutual Friend II. III. ix. 78, I don't like to hear you depreciate yourself.
3. intr. To fall in value, to become of less worth.
In chapter 37 of Dombey and Son, Dickens is using meaning 2.

Finally the entry for the verb we would expect him to use. Note in particular the quotations offered for the "draft additions 1993". I have taken all the entires from the online version of the OED. I assume the additions are not in the print version. Presumably entries 1-5 would have been the "a." since the draft additions are said to be "b. More generally…" I have removed the quotations from the main entry but left those in the appendixes.
deprecate, v.
Pronunciation: /ˈdɛprɪkeɪt/
Etymology: < Latin dēprecāt-, participial stem of dēprecārī to pray (a thing) away, to ward off by praying, pray against, < DE- prefix 1b + precārī to pray.
1. trans. To pray against (evil); to pray for deliverance from; to seek to avert by prayer. arch.
†2. intr. To pray (against). Obs. rare.
3. trans. To plead earnestly against; to express an earnest wish against (a proceeding); to express earnest disapproval of (a course, plan, purpose, etc.).
4.
Etymology: < Latin dēprecāt-, participial stem of dēprecārī to pray (a thing) away, to ward off by praying, pray against, < DE- prefix 1b + precārī to pray.1. trans. To pray against (evil); to pray for deliverance from; to seek to avert by prayer. arch.
†2. intr. To pray (against). Obs. rare.
3. trans. To plead earnestly against; to express an earnest wish against (a proceeding); to express earnest disapproval of (a course, plan, purpose, etc.).4.a. To make prayer or supplication to, to beseech (a person). Obs.b. absol. To make supplication. Obs.
†5. To call down by prayer, invoke (evil). Obs.
DERIVATIVES
deprecated adj. 1768 C. SHAW Monody vii. 61 Why..strike this deprecated blow? 1839 Times 11 July in Spirit Metrop. Conservative Press (1840) I. 158 To persist in such a deprecated and odious innovation.deprecating n.
DRAFT ADDITIONS 1993
b. More generally, to express disapproval of (a person, quality, etc.); to disparage or belittle. (Sometimes confused with depreciate.) Cf. self- deprecation n. at SELF- prefix 1a. Widely regarded as incorrect, though found in the work of established writers. 1897 Daily News 8 Jan. 6/3 It looks rather an attempt to deprecate distinguished commanders of the Commonwealth to please Restoration Royalists. 1927 V. WOOLF To Lighthouse I. viii. 70 He was disposed to slur that comfort over, to deprecate it. 1960 C. S. LEWIS Stud. in Words i. 18 We tell our pupils that deprecate does not mean depreciate or that immorality does not mean simply lechery because these words are beginning to mean just those things. 1965 M. FRAYN Tin Men xv. 80 Trying to shrink into himself, as if to deprecate..his authority and to become as other men.
 So self-deprecation is "widely regarded as incorrect". It is not surprising that the earliest quotation for self-deprecation is almost a century later than the earliest for self-depreciation. Nowadays self-deprecating (or acting in a self deprecating way) is almost a synonym of modest. In fact it means self-cursing. On the other hand to depreciate means to lower the value of. It is one of the perversities caused by income tax that depreciation of assets is something to be sought.

I haven't read Our Mutual Friend so I do not know the context of the quotation. But James Carker who gives Edith the self-depreciating smile in Dombey and Son is far from being a modest man. He puts on a modest front but is always described by the narrator – who recurs again and again to Carker's teeth – as a shark.

It might be that before it was supplanted by self-deprecation, self-depreciation had more of a sense of hypocrisy. Certainly James Carker is a flatterer and a hypocrite.

Note the quotation from the Hare brothers' Guesses at Truth (ser. stands for series not, as I thought, sermon – both brothers were Anglican clergymen). This is a miscellany of "detacht thoughts", consisting of a series of longer and shorter "Maxims, Aphorisms, Essays, Resolves, Hints, Meditations, Aids to Reflexion, Guesses". Those are both quotations from the opening (not strictly a preface, the work proper begins in a following paragraph), which explicitly connects their work with (inter alia) that of Solomon. It is meant to be like the wisdom literature in the Bible. Its nearest modern analogue might be The Little Book of Calm (et hoc genus omne) which used to occupy the space around cash registers in bookshops, which is now held by great works of literature rewritten as tweets. Anyway the full maxim, printed between two horizontal lines, after and before unrelated matter, reads as follows (on page 295 of the edition at Google books):
Self-depreciation is not humility, though often mistaken for it. Its source is oftener mortified pride.
The quotation from Giddens in the entry on self-deprecation is interesting (saying that there is a "range of possible forms of self-aggression, which extends from … verbal self- deprecation to actual self-destruction"). It represents the philosopher's urge to put everything on a continuum. It is not as though someone modest about his achievements has simply got off the train earlier (so to speak) than the suicide. If I am right about self-depreciation having a sense of hypocrisy (which is certainly not the case with self-deprecation) then perhaps Giddens is accidentally reimporting that sense into the replacement word.

At some point depreciation became a technical term used by accountants and therefore self-depreciation became a nonsense. It might even be an effect of the easier spelling of self-deprecation.

But what would I know? I never took a course on lexicography or linguistic theory.