There is a very simple solution for this kind of thing going forward, although it may be too late to reverse course with this girl since a precedent has already been set. I NEVER pay for non BCD dates, NEVER. I have on a couple of occasions given the girl a few bucks because I felt sorry for her on a date where we didn't go BCD, but I made it very clear that she wasn't getting "paid" for going on a date with me, but that I just felt bad for her circumstances and to just consider it a one time gift.
I don't mind at all going on non BCD dates, but let me repeat "I NEVER pay for them" it just sets a bad precedent and ultimately leads to the situation you now find yourself in.
The good news of course is that losing her won't make much of an impact on your life so you still have a chance of saving this. Here is my suggestion. In sales you are taught to Isolate the objection, agree with it, and then "overcome" it. The objection of course is she needs "more money" IMHO you need to agree with her (whether you actually do or not) that you understand that she has needs, and then suggest you two go for Quality over Quantity, IOW Suggest to her that you guys see less of each other (This keeps you from looking like she has the upper hand) but that the times you do see each other are more of the $300 dates and less of the $100 dates. Personally I think you should do away with the $100 dates altogether, not just with her, but I think you should take them TOTALLY out of your repertoire.
Lastly, you might also consider making the 16.6% "raise" permanent, I am sure it makes no difference to your pocket, but it might incentivize her into having more dates like your last one. It's also a solution where you can both feel like winners. You certainly don't want her resenting her dates with you. This way she gets more money and you get more pussy, sounds like a win/win to me.