Silly feedingquestion but please help!

FTM115

So my 11 week old has reflux and is on prevacid and thickened feeds as advised by GI specialist.  I have been asked by specialist how many ounces of milk he takes in 24 hours. Here is  where I need some help. His bottles are 3.5 oz. but once I add formula powder (1.75 scoop of similac advance) and 2 tsp of rice cereal, it's 4 oz. So if he finishes the bottle, I should count that as 4 oz. per feeding right? I am not sure how precise I need to be next time I take him for his appointment, but I rather be sure.

 Sorry if this sounds like a stupid FTM question but your thoughts are appreciated.