Yea no worries about some variability in temp... generally lower temps in that range will get you more maltose so it will be a lower FG in the end, higher temps will be a higher FG/ less attenuated. 154 is a nice middle temp and i usually use about a 152-156 range due to the low level of engineering of my system, which consists of a large rectangle cooler i found on a beach one time that doesnt even close all the way.
Primary: SMaSH-Galaxy/Crisp Maris Otter,SMaSH-Topaz/Fawcett Halcyon,Bohemian Bulldog Steam Beer,Causeway Kolsch
Secondary: SMaSH-Rakau/Crisp British 2Row Pale
Bottled: HeftyWeizen,La Flama Blanca Pepper Wit,DunkelRyeZen,Big League Brew Wheat IPA