Man, come to think all these years I have been flying close to 50' HAT, and have thought all the calcīs. were done taking that into account, and I realize now that every time I make a visual, I might be crossing the thr. below half the dist. I thought I was at some smaller airports
That's right. But to help you, the AIP information for the airport you are operating in to should have the threshold crossing height of each PAPI for each runway printed on the aerodrome chart or elsewhere close by.