Designing Kitchens and Bathrooms - Vapor Barrier Question

I'm doing a complete, down to the studs & subfloor, renovation of my master bath. I've never tiled before, so I have tred to read all advice carefully (notice I did not say 'follow' ). For the shower area, I put in unfaced insulation along the exterior wall and stapled a continuous sheet of 6 mil plastic across the entire wall. I have the shower pan (Swanstone) against that wall and the instructions say to drop the vapor barrier over the lip of the pan and caulk the inside edge of the plastic, then put Durock on top of the plastic followed by tile. Here's what I did instead: I have the plastic going to the floor behind the shower pan, then, on top of that, about two feet up, I stapled another row of plastic which does come down over the lip of the shower pan like it's supposed to. (I'd explain my reasoning for that, but I would have to think too hard to come up with something.) My concern now is that any moisture that gets behind the Durock will run down the plastic and straight to the floor below the pan, instead of over the lip of the pan, since it will go between the two sheets of plastic. I have tiled the wall except for the very bottom row below the ledger board, so I could cut through the Durock and attempt to correct this situation. Before I do, I'd like some expert advice as to whether I really have a situation that needs correcting. Any takers?

Why didn't you follow the manufacturers instructions. What you did, as i understand your description, is provide a path for moisture to go behind the partial barrier you installed, down to the subfloor. What they recommended is correct.