Im sure @abidamr means well but I also get that feeling @ectoplasmosis. What would help here @abidamr if you plan on more of these posts and if you are using AI? is that you use it to summarize what you want to say in as compact a form as you can.
As I read it, your core point is that you were able to run your system at a lower flow temperature on the coldest days than you expected, 46C briefly at -2.7C, 44C during day, 39C at 5C outside vs 50C design temp.
That’s great that you find this and it is consistent with what a lot of us are finding. If I can plug my own work 
you might enjoy What SCOP can you expect from a system that runs at 55C and 50C flow temperatures on the coldest days?
What I don’t think is clear enough from your analysis on this page at least is how you are only targeting the upgrade to 2 radiators. Are the room temperatures higher than expected in the other rooms?