So, what’s going on there is that BOM adjusts *to* a year, but *from* each quarter individually. Or at least, that’s what the dailies display, I can’t vouch for whether the dailies adjusted to year N actually add up to the total displayed for year N.
2015 had the following data:
Q2 price 8.61
Q3 price 8.25
Q4 price 8.70
yearly price 8.43
For the days in and after October, BOM applies the Q4 price for JW and adjusts it down by a ratio of 8.43:8.70.
For the days before October BOM applies the Q3 price for JW and adjusts JW’s gross up by a ratio of 8.43:8.25 — even the portion of the gross in Q2, which is a mistake.