in my actual setup now things are more stable and it's currently under observation, I am getting a good reading between 350-500 from all 4 probes and there is not much fluctuation.
By saying actual setup I am saying the complete system and approx. 500 lines of code including different sensor modules, display and buttons e.t.c I have mentioned in my first post so its a LIVE environment now.
Not sure if it is too early but I think its safe to say that my challenge around unstable readings is now fixed, even if not then also I have that level of control to read what It suppose to.
I am going on vacation soon and will do a full cycle of testing after one week to fix some other bugs.
Thank you for your help on this Steve.