Samsung Mono R290 FSH Inertia

Dear all,
After some observation, I found that the FH inertia is not directly handled by the Samsung ASHP controller (I guess on my AE050CXYBEK/EU all in one outdoor unit, the controller is very likely a MIM-E03CN).
The observation I have is that to reach 21C, I must stop at 20.5C, else, the heat inertia of the FSH will make the heated floor to go past the 21C largely (it generally raises a fat 1C over the target temp).
I couldn’t find any FSV available that controls this thermo off setting. So, as the HP is well integrated with Home Assistant, I wrote an automation script to do it.

1/ Has anyone had the same question, is there some obscure configuration I missed?
2/ Is there any possible drawback with my inertia handling?

Cheers,
Topaz