My personal; opinion is that with Wagerlogic, Microgaming, Wagerworks and probably Playtech that fun mode replicates real mode. Reason I say that is that I don’t think these software providers would be prepared to risk their reputation by doing it any other way.
However, with RTG, operators can change the payouts within certain boundaries but I would imagine fun mode is set to the uppermost boundary – a guess.
There was some outcry recently when it was found that one software supplier had different payouts on fun mode and in real play. Enough of an outcry to effectively rogue them in many people’s minds. I can’t imagine MG and Wagerlogic differing them personally, but who knows. MG in particular seem very reluctant to offer information to the public domain for whatever reason.
I think I’ll find out at ICE. Or try!