Wool of the Andes Gauge

Wool of the Andes calls for 20st/4 in. on US 8s. I swatched tonight on 5-9 in order to see how the fabric turned out and what it took to get gauge. I had to go up to US 9 Denise needles in order to get gauge. Now I just need to decide how much ease I am going to need in the sweater. The finished measurments include ease eight? For example, if I have a 36 in. chest (I wish) and want an inch or two of ease I should knit the next size up rather than the 36" small, correct?