Any increase to interest will mostly go to exchanges unless there is a massive movement off exchanges, which seems unlikely. Upbit and Bittrex together hold 4,554,613 HBD. That is 44% of the total before hive.fund is removed, and 73% if hive.fund is excluded from supply. They are not giving the interest to traders, and I don't think that will change. Only 16% of HBD is held in accounts other than those 3.

IMO the increases should wait until after the hard fork.

Edit: I suppose it could be worth having the increased yield as a marketing talking point alongside the hard fork. It's just that most of the interest generated before that fork date will end up as a freebie gift to exchanges.