I reported that I hadn't seen that, but you say the guide works perfectly, eh?
Well, even though it is off-subject, here it is. You made me wonder what would happen, so I kept in mind your question while researching the stuff that can be affected by an installer. I am only really interested in stuff that a person can do to increase a bad picture, or optimize a system.
But, the answer is that EPG information is a static, basic, two or three color presentation that doesn't require anywhere near the amount of information to decode vs. a high definition, moving picture. (And even far short the amount of information a standard def digital picture needs.)
You're gettin' this, aren't you?