Going deeper here, what if the list has 5 things to check on it, and they all are just visual things, and the homeowner don't know any better? Well you have done your job according to what your company states what is involved in a PM. Most homeowners are good to go with just seeing you check the freezon.
Everyone runs their business differentially, if you are doing a PM based on some of the lists I have seen in the past 30 years, your would be there half a day, so most PM lists are like a buffet for most company's, I will check this, and that, O that looks ok.