Pakistani developers...? SAMSUNG updates are developed by its software-Engineers team not by local developers. Samsung software department do take inputs and suggestions from local developers and make an OTA accordingly..
battery drain after an update is a common problem.. it depends upon user that how he or she deals with phone.. battery drain also depends upon software optimization. In case of Samsung, it is difficult to send users a perfect optimised OTA due the fact that Samsung has a long spectrum of different phones. Software department falls short due to over burden.
software Updates Budgets Included in Phones Prices And There Agreements At Least 2 Years. So They Need Work Well Not Only Put Copy Paste Roms Likely They Just Change The Country Region's And Put It in OTAs but in Others Countries First They Check And Then Put In OTAs This's The Main Difference.