Warren, I had an older Pedersoli and the sight acted as you mentioned, i.e. It would not fold back, only forward. The Pedersoli sight was designed to be mounted in two ways, depending on what kind of rifle it was mounted on. I found that in order to get mine to work correctly (with the long leg of the base on top) I had to carefully modify the detent for the spring in the sight base. I took just a bit of material out nd the sight then operated correctly.
Actually I still have that sight, but not the rifle. It works well, especially with the Hadley I added to it. It is bulky as heck though.
Edit: i should add that there is some adjustment in the spring, but it was insufficient on my rifle. I imagine that you've fiddled with that already?
Chris.