Gauge problems.....ehh

i’m trying to make the back to school u neck vest from fitted knits and i made a swatch, as directed by the pattern using the waffle stitch that will be used on the top portion of the vest on size 7 needles. my gauge is a little tight so i’m going to try swatching with size 8 needles. my question is, the bottom portion of the sweater is worked in the round and is just ribbing on size 5 needles. if i need to go up a size on for the top part of the vest, do i need to go up a size for the bottom portion also?

The only way to be really sure is do another swatch for that stitch section as well.