Holy hell, that's a huge tank. My LFS has a 10ft x 4ft x 30" display with a 9" L200 green phantom that made the acrylic look like someone wiped it with sandpaper.
Are you sure the L200 caused this. If that display tank has been around for awhile, is there a chance other things may have caused the damage over the years. My acrylic has some age to it now along with many fine lines throughout. I chalk it up to thousands and thousands of times my aro and dat might have grazed their pectoral fins against it. Or my loaches as they fly around the tank at times swiping their fins against it. Or when i'm cleaning the acrylic with the cleaning glove, sometimes a few pieces of sand get stuck to it and then as i'm cleaning..the few granules of sand will put fine lines in it. Not saying some species can't mark up acrylic tanks some with their teeth, just an overblown thing imo in general. I never see my plecos on my acrylic panels, even at night if i have to take a leak and put the hall lights on..never see them on it.
There must be somebody here that bought a brand new acrylic tank and has only had plecos in it from day one that can give us further insight & pics to prove or debunk the theory some