No, they don't mention this issue on the site. They tell you generally how to service the valve. Cleaning around that little hole is extra-credit.
It's an issue I know enough about the valve to tell you how to fix, but it's not a common issue. Cleaning that area is mentioned on this Toto piece, part of Item 8 on the Type B valve:
http://www.bayplumbingsupply.com/images/documents/voretolavallefillvalveinstructions-rev06-1.pdf
The reason you can't replace this with a 400A is that you won't get enough refill. A GMax Toto requires a 40 percent refill ratio; the 400A produces the standard 20%. If you don't get enough refill ratio, the water spot in the bowl will be too low -- eeew -- and when you go to flush part of the flush water will be used to raise the level of water in the bowl and the flush sequence will be off; i.e. the performance will be degraded.
You want to replace it, replace it with a Korky 528MPK (or MP) from Lowe's. That has a variable refill ratio, from zero to 40%.
I actually think the 528 is a much better valve than the 400A. I'm not going to give you the litany, because there are old timers on here who swear by the 400A. Suffice it to say that you're doing your relative a disservice by going the Fluidmaster route, particularly since anything on a 528 can be fixed very quickly and easily by non-professionals. And if it's important to you, the 528 is made in Wisconsin while the 400A is
hecho en Mexico.
So just get your relative to run his finger over the bottom of the valve and see if that doesn't fix it. If not, a quick valve service should do it. Then leave it alone, and it should work great for some time to come.