Propane in summer weather and fps variations

[Szevin]

So the KWA kriss vector shoots roughly 360-380. I'm wondering how much higher will it shoot in hot summer weather? Say 380 is it's norm. Would that be going off of room temp that it's tested at in Taiwan somewhere? Lets consider they like their rooms at a comfortable 20 degrees, how much do you suppose the FPS would rise in say, 25-30 degree weather? Ultimately I'm worried about shooting over 400 and thinking about picking up an NPAS, but I dont want to bother if it won't likely be shooting over 400 in hot weather.