Demo or fun mode sometimes has a different RTP tho because of different settings. For example, the site may use the ~94% RTP version for real play, but it's still ~96% on the fun mode. Always check RTPs

Anyway, do we have to contact the support for each rank up? Or just one time (for the first rank up)?
Is that really what it is? I thought that real play and demo mode has just the same RTP. Is there any articile or from anyone or anywhere that can verify it? Too bad, I was expecting that they both have the same RTP, I played a lot of demo before to test which slots are the best for investment.
Now that you've mentioned about ranking up, can't remember that I ranked up on Heart rank before they implemented this VIP system, I never contacted their support tho, can I still get my rewards? If I'm wright I was already on heart rank since then.