Why $4.05?

I didn't do the exact calculation, with rounding that was 11.9 * 2 STEEM * $0.17, based upon the rewards payout in the steemitblog wallet (then doubled to account for curators). I think we're in agreement now on the discrepancy.

I strongly suspect that this is the case. Until the TRX rate were set to zero, it was not possible to reproduce the values.

The funny thing is, I vaguely remember a conversation some years ago (pre-HF23) where they debated whether to display the value in SBD or use the currency label ($). IIRC, the argument was that it didn't matter because SBDs were pegged to dollars.

I don't remember the topic of haircut pricing being mentioned, though. Maybe it wasn't covered, or maybe I didn't catch the significance of it. Clearly, it does matter.