GKLL Coverage Compared to CGL Coverage

Our insured is considering moving from one carrier to a new carrier. The insured is a radiator repair and windshield shop. Rather than keep garagekeepers direct primary coverage, the new carrier is proposing that the insured use the general liability policy and add endorsement CG 22 68. This endorsement is called “Operation of Customers Autos on Particular Premises”.

We see this endorsement as a liability endorsement that limits coverages for the customers' vehicles compared to the garagekeepers coverage. The underwriter feels the coverages are equal. What is your opinion?