Gary:
1) I think your technique is still there on the PSn (and pulling technique still matters some - keeping the bar close etc), all of that muscle memory doesn't just disappear - kinda like how I can still drive a golfball well after a layoff (but can't putt or chip for shit), so that's probably part of it. Like it or not, while you think you were testing power (mentally), there is still some technique involved here that matters quite a bit.
2) You were pulling the weight, not squatting it. I think this makes a difference here too. Now if you had told me you were doing Snatch and got stuck in the hole with the weight overhead and had to bail - whole other story. Is your deadlift still pretty good? That slow pull equates more to the PSn imo than your squat.
3) I suspect you are stronger than your 175# squat session leads you to believe, but that you aren't used to the weight (I have a similar issue with layoffs, but I'm a bit older, so it's even more evident). I suspect that the ability to carry the heavy weight and recover will come back pretty quick relative to what it took to gain the strength the first time around. You're not mid-300's strong still, but stronger than a 200# squat too would be my guess.
Nice to see you around btw.