Is this her ignorance resulting in an overestimation of his ability, or an underestimation of it? Or are ratings strictly in the eyes of the rater - unless there are specific guidelines from management on this issue......I'm gonna go home and see what I have in my mailbox and then go inside and test my recliner....
In the late 70s, as a college student, I took my car to a mechanic who was mentally disabled, could not read, and had trouble talking. However, he had an intuitive understanding of mechanical things. On one occasion, I needed a new (used) transmission. There were no transmissions for my model car available at any nearby junk yards. But he went out and looked at the ones that were available and picked one he said he could make work.
He took it apart, cleaned it up, put it back together, installed it, and there were quite a few parts left over. "It will work better without them", he said. He was right, except there was no reverse light switch in that transmission. So I installed a toggle switch on the dashboard, which got me through inspection, and gave a nasty surprise to quite a few tailgaters.
Sadly, electronic systems were completely beyond him, and he was able to do less and less work for me.