It's bollocks. The RTP is clearly at factory setting for the demo and nothing to do with geo-location as although casinos COULD theoretically offer different RTP's to various markets according to their taxes and profitability, the move would be suicidal once Helmut Fetter in Germany saw he was getting 94.2% and Dick Splash in Canada was getting 96.2%.
The variable RTP slots which are demanded by operators in recent years are just that - operator set via the RTP range menu. It's been a big selling point for developers. They are no different to @ChopleyIOM
AWP fruit machine dip-switches - you set the option, that's what the punter plays.
So in this case the free slots with no account linkage or integration are clearly being left at factory RTP and when in actual play are presented lower. You can run several maths models at once of the same game according to how many separate places it's placed.
The WHOLE range of RTP's is available off the integration menu for the customer (casino) and it's not a case of ordering a slot from Play'n Go and while you're doing it opting for a fixed RTP version off their 84-96% list as some seem to think which the casino cannot change. RTG casinos have been doing this for years (some) offering 97% when free chip bonuses for new players are in play and then afterwards 91% on cash deposits...
It's a clever answer from N1 - Yes, the RTP is set on the game provider's side (game server) but the missing part is 'i.e. the RTP we choose.'
I think those screenshots are pretty damning and N1 have some serious questions to answer here. Indicative of serious fuckery IMO, demonstrating the benefits of operating under a meaningless Cup-o-cocoa license or flaccid MGA license. That in fact compounds the issue, as with lower taxes and costs than under proper jurisdictions like the UK, Sweden, Germany etc. there's no need to lower RTP's.
In the case of Coral here in the UK, the issue was different - demo and real play were the same and had been reduced to 94% but their long list of all slots in their casino customer help file was still displaying the old 96% values for a few weeks.
In proper jurisdictions like the USA, UK etc. offering different-value products for test then inferior for real money is about the biggest no-no you can do under a gaming regulator or general consumer laws. But send your cash to a banana republic, expect to be treated like one.
Perhaps they had to lower the RTP's to fund R*shte*n's 'real money' monster wins and withdrawals...