Welcome to the Forum!
Lots of information here:
out-of-round-circles
First step is to check the calibrated numbers with what you measure by hand.
Primary numbers to check in this pic:
If one or more numbers seem off from what you measure, change them.
The Forum Wiki has ‘how to get calibrated’ How To: Get Calibrated! and ‘list of errors’ List of sources of error.
It will take some likes, responds and activity, before a new user can upload pictures or the groundcontrol.ini file if deeper digging would be required, but from what i know in 1 or 2 days that should work.
Kind regards, Gero