So the "current RTP" (some calls it TRTP) graph fluctuation is per player, on each game, in each online casino? The technology is available for that, but I think this method won't be good for players since the end result will always be less than what we put in.
I've been trying to find info how online slots RTP actually works for a long time but haven't found a definitive answer. For offline slots it's easy to understand: RTP fluctuates on each individual machine, no matter who plays. Online slots are a different, just not sure how exactly.
My best guess is all players, who play one particular game, at any given time, from every online casinos, are jumbled together, at the aggregator, to calculate the current RTP (aka TPRP.) Or maybe the online casinos grouped into clusters to avoid server overload at the aggregator.
Still waiting for info from someone who actually know.