It's unnecessary. If it's difficult to work with, get rid of it. I don't have plastic sheeting in my pool.
Thanks for your input, Dave. The previous owner sounds ever so slightly familiar. Lol. I'm sure in the end my extra effort will be worth it and I won't worry about imperfections as much since I read your post. I think your algae reference may be leaning towards a 'yeah' for my extra liner. (Casey, I just saw your post.) Once I removed the foam cove from the plastic it was easy to work with. A few of the foam cove pieces are slightly scrunched at the corners, but with the pad appearing to reach over , I'm not going to worry about it.
I'm pretty comfortable with all the foam at this point. How far up did your pad go over the foam cove, Dave? This one is cut unevenly but at this point I think my dedication to perfection is waning. I'm going to trim so none is over the cove bc I'm thinking it would show with a tight liner??? I'm not expecting the gorilla pad to be too forgiving and there are some very minor wavy spots too, hard to describe.