Maybe it was an inspection change. Instead of inspectioning every rifle they only did every tenth one.

GM removed their on line water test booths in the late 90's. They had a booth at the end of the line and tested every tenth car before it was shipped to the dealer. I can't even begin to tell you how many dashesI removed from the 89 Cadillac Devilles for a water leak around the heater module from a bad gasket seal.
Al