milk

Ok I'm very paranoid now . My baby is reaching 4 months old on 9 dec . And weighs 6.1kg . He just recently changed his milk powder from stage 1 mamil gold to similac total comfort stage 1 . Reason for changing because it stated it's good for baby who have enzymnia or to prevent enzymnia or smth like tt . Well his rash seems to be getting better but what concern me now is the amount . It stated for his age the feeding instruction is to give him drink 180ml . N my baby got this regurate problem. Plus now he got this habit rlor dunno isit he discomfort or what ,than he will drink halfway than start to wiggle n cry . Like he is piss with smth . I change his diaper etc but still he dunwan drink finish his milk . Got one time he drink 1/4 only than he start his nonsense again . For mamil gold its 150 ml but it seems to make his rash abit worst . I dunno . Is there any milk that u all can recommend like for 4 months old but in lesser amount each feed for every 4 hours . And suitable for baby who easy get rash . I'm very paranoid now cause he keep dunwan drink finish his milk n keep crying not happy with the milk ?