You're good! If you don't see IR there is nothing to worry about. Never have to burn in the TV anyway. Slides just age the TV at an accelerated rate so you can get it calibrated after owning it for the minim period of time.
I'd say you actually made out pretty well. I'm assuming you have been watching regular programming as well? You've watched the least offending content in those movies, only small slivers of black, and because you don't see IR I'm assuming the regular content you watched didn't have a nasty network logo.
Those movies amount to what, 20 hours? Just keep on goin on the way you've been watching. Avoid a lot of letterbox and it's cousin the un stretched 4:3, As well as nasty network logos and tickers. (20 hours isn't really allot)
Watching nothing but letterbox is bad, unless you zoom, and same with network logos.
If you want to get out of the danger zone more quickly, go buy a tactile turtleneck and run slides or a 60-70 IRE greyscale window when your not actively watching TV. I'm also going to guess that you flipped out into movie mode at the very least, or you have turned the contrast down to get it out of torch mode. If you used a cal disc for this, you may want to drop the contrast around 5-15 points when your watching something with a logo. (that's just an estimate, I don't own a copy of your set. Just know you don't have to drop it to the o point of "this picture sucks". These are all just rule of thumb things to do in your first 150-200 hours of use. If you do end up running greyscales go ahead and subtract that time from the 200 hours.
You can take these suggestions with a grain of salt if you like, as you don't have IR from what you've been watching. What I've listed above takes care of the worst offenders, but so does varying the content a lot, which sounds like what you've been doing. Damn, I've been meaning to upload the old avia SD disc to my website. that will give you greyscale and color slides to run through checking for IR, but other than that the greyscale Windows (you have to stretch them for full frame accelerated aging) and learning about home theater is ask the SD disc is good for. You don't want to use the color windows for anything but checking. If you want to "run slides" you would want a source put together just for that purpose. If I get around to uploading avia I'll let you know. In the meantime you'll want to pick up a copy of the Disney WOW disc for front control calibration and the pixel flipper. Out of everything in this plasma thread, I think that's the most universally accepted advice.
As always, you paid what?, a couple grand on something to provide good entertainment? So don't let all the crap I just typed get in the way of your enjoyment of your new set. As you have found, 20 hours of letterbox isn't going to screw your TV. 20 hours of watching the same channel with a nasty logo however, WILL likely get your panties in a twist!
No offense there, just the saying, and we are talking about something you paid a few grand for. So watch smartly and enjoy that baby!