I'm sure you understand what was meant, Kahn. By 'rakeback' posters, including me, often mean aggregate returns from all rake-based promotions - the central VIP program (up to 35%), reload bonuses (that clear at 10% and afaik can be triggered one after another at PH) and affiliate-specific promotions like rake races. Total returns may exceed 70% of generated rake at times.
There's a 35% cap on its component proportional to the rake generated (in absence of reloads) aka the central VIP program, and a 10% cap on returns from reload bonuses. Thus 45% is guaranteed to a player with >$30K lifetime rake who reloads diligently.
Anything above 45% is not guaranteed: it's theoretically possible that 50 Leatherasses sign up and rake $10K next month and kick $2K rakers out of the race prize zone
, but normally this doesn't happen and these rakers get solid hard-earned prizes
Afaik Merge skins are still allowed to give away as much as they want in races, there's no such strict promo budget regulation as on WPN/Party/888/MPN, apart from the mentioned caps on VIP rewards and bonuses.