So, I might be catching up to what others may already know, but here it is. My oven has been struggling to reach the SET temps the last few weeks I talked to an appliance tech and he said to check the igniter bar on the broiler and bottom. Everything seemed fine. Then a little interweb searching I found that there is a 'special functions menu' that can be accessed to change several things including adjusting your oven temp up and down 35°! Turned it up 35° and things seem to be working much better. Changed the clock to 24 hour military time from 12 hour, will drive the Warden nuts, she refuses to grasp it
Anyway here's a link, pretty straight forward.