I was told prime plus 2-3 when I was shopping for a commercial mortgage a month or so back. Undoubtedly lots of variables - the quote was "quick and dirty" - no appraisal, no credit app, etc.
Sound like good advice.Why not take the rate you are currently charging them and go back and see what the prime rate was when it started/when they last renewed... if it was 2 over prime then, just use 2 over prime now?