Commodore Canada never did the mod on any A1000's they repaired. Comspec usually did the ground mods on all Services A1000's at least I always did on any units that I Serviced. The mod was a recommendation if any devices were to be chained from the expansion port.
Using the Mod When I had an A10090 I had 2 AX1000 (2MB Memory cards) and the SA1000 (SCSI Controller) connected and had no issues running any applications.