I'll agree with this, and will add in my own opinion that an off square rear end is a crutch that costs lap times in the long run.
Many handbooks written for Racecar Chassis Setup have also suggested running a square rear end,
-Paved Track Stock Car Performance by Steve Smith (pg 132)
-Stock Car Setup Secrets by Bob Bolles (pg 51 and throughout Chapter
-Chassis and Suspension Handbook from Circle Track (pg 56, 62, 116, 136, 141)
-Finish Line Racing School Chassis Manual by Mike Loescher (pg 110)
Once we had learned this and to align the right side contact patches with one another, our car really took off. We gained time /lap since last year w/o changing the baseline setup.