dunno, are you AC or DC.
Oh, wait, I didn't read the post, I just read the title.
Theoretically you should get it serviced, but I never have. I clean the unit & service the fan motor myself, but that's it.
The temp can vary a few degrees from what you have set, for several reasons; Faulty thermocouple, bad thermostat placement, vis-a-vis air circulation. It's not really an absolute, more like a relative setting. If you want it cooler, try lowering it & see if the temp goes down accordingly. Plus, the 100 deg outside may be a little much for your unit to handle.