I know Frank in not a BSer, but he is capable of being wrong like anyone else. It makes no difference how many stones Travis carved, or how many maps he may have made. I tend to believe he found the PSM's like he stated in his own words.
A few years ago on a debate here about which stone he found first, I stated that it could be no other stone than the P/H stone. This was because it is the stone that tells you it is one of four stones, and to look for the others in the same hole. I said it had to have being buried edgewise with "Miguel" visible. This is what got Travis attention, and it turns out that I was right. I also know in which position the stone was buried.
The stones that he did carve, show that he was incapable of having created the PSM's, and the hole where the PSM's came out of also tells me it was impossible for him to have buried them so precisely.
All this without even going into what's on the PSM's.