Higher mash temps lead to more unfermentable sugars, which will lead to a higher FG as the yeast can't consume unfermentable sugars.
I would suggest picking up a copy of "How to Brew" by John Palmer. It explains this and a lot of other essential subjects homebrewers need to know.
i see. that makes sense. thanks! I'll be picking up a copy soon. still learning all this crazy chemistry stuff. :cross: