Should be
nSubsidy = nCoinAge * (COIN_YEAR_REWARD / STAKE_DIVIDER) * 33 / (365 * 33 + 8);
You have STAKE_DIVIDER in the wrong spot. This is not a very clear way to do this whole switch, though
33 / (365 * 33 + is the calculation to get the average value of one coin-day (including leap years), so putting STAKE_DIVIDER where you have it will fuck with that formula, and will give you stake rewards you are not expecting, rather than adjusting stake rate
How would these "unexpected" stakes manifest themselves?
Just asking because during the last month I have on occasion been getting a stake or two that seemed out of the ordinary, I just never gave it much thought.