The mistake you continue to make is that the reality is that two guns in different condition are worth different prices.
You haven't actually examined any of these guns, so I don't know how you can determine condition. I can only comment on what I've seen. The pistol I purchased shows only some external holster wear. The gun was filthy, but after cleaning I found it was like new internally. Everything locks up tight, the barrel is like a mirror, etc.
I'm hearing the same reports from others who have purchased these. Remember, these aren't veterans of the six day war. They are cop guns that were carried a lot and shot very little.
The bulk of these are the late 80's to mid 90's "contract" (Mark II 1/2 as they are sometimes called) guns that can be recognized by the little ridge running forward from the trigger guard to the front of the frame. Those, universally, seem to be in great shape and a great value at under $400.
Along with the contract guns, are a mixed bag of other Hi Powers in varying condition. Some are late 40's guns. Some of them are captures from Syria or elsewhere. Some of them are Frankenstein guns mixed with FEG parts, and there's even a few of the "Kareens" which have disputed histories.
Anyway, with the "contract" guns I don't think you can go wrong. With the others, you may get a gem or not, but that's for the buyer to decide.