I have had similar experiences.
My preferred vet for PPEs was a long tenured, crusty old soul who didn’t care if she pissed a trainer, buyer or seller off and just called them as she saw them. Now, not everything made it into the written report, but I got great info from standing next to her watching the horse go.
Also, on the PPE forms with which I am familiar, there is a spot for “purpose intended”; eg, light trail riding, local showing, dressage, eventing up to _____level, etc.
The conclusion of the assessment states that the horse is servicably sound for purpose intended, servicably sound for purpose intended with reservations (listed below) or not servicably sound.
80% of the PPEs with which I was involved were the middle category, serviceably sound with reservations, and the difficulty, especially for new horse owners, was reading the list of reservations and deciding what was critical and what wasn’t. This is absolutely where you want a pro’s or knowledgeable friend’s opinion on the findings. Things like an old cold, splint, high up on a foreleg are easy to give a pass.
In the Heritage case, a 6 yo pony with coffin bone rotation visible on xray? That had to be nerve blocked to compete previously? Yikes, yikes, yikes, yikes.
I feel certain that I have seen cases where the seller substituted a sound plain bay horse for an unsound one, or a different grey pony. I hope microchipping has put a stop to some of that.