The percentage figure shouldn’t be the top priority since each affiliate program has different approach on how they calculate affiliate earnings. Some casino get the affiliate commision on the total amount lose by other user and some casino like Stake counts the total wager for affiliate earnings including winning bets. So the affiliate structure should be considered to find a suitable replacement on what OP asking.
I’m not familiar with BC.Game Affiliate structure but Stake and Bitcasino has a very good affiliate structure which I believe that can use by the OP to replace his old affiliate program since I'm sure that he can easily climb higher tier due to his strong affiliate network to get the maximum tier for the affiliate program.
Totally agreed, an affiliate program that pays on the total amount wagered by the referrals including the bets that they have won themselves are much better for affiliates than the ones who only pay for lost bets or something like that. If someone has high rollers that bet a lot of money every week or every month, an affiliate program like Stake's can definitely serve pretty good considering they will be paid for every single bet their referrals make.
So for OP, it's probably the best if he takes his referrals and migrates to Stake, or if he finds another platform that has a better percentage of commissions paid for each wagered bet, he should choose that, but overall, Stake seems to be perfect for this.