Question about formula

Veronica • George Alek Jr 4/08/17💙 Layla Jae 8/16/2018💜 Currently pregnant due in November
My baby is on similac sensitive formula and he'll be a month on Monday,and he went from drinking 2oz at one time to 4oz..and I know that's normal but should I switch his formula too,to a different kind of Similac..we see his doctor on Thursday so I'll ask then but just wanted other mom's opinions on what you think the doctor will say lol