I myself thought both were wrong. But I have no scientific evidence, just my thoughts.

1: if someone takes only a small amount of mestinon (in comparison) it can also mean they have a very small amount receptors left, and will have cholinergic symptoms very soon, and mestinon will only help a tiny bit. In this case, giving less or more will both cause weakness. So in a sence, they have a more severe MG because they have less receptors left in comparison to someone who benefits from higher dosages.

2: it leaves the body very soon, so you can't compare the maximum daily dose (if this is 1250 or 600 mg, doesn't matter). Because this is the maximum dose you can take in a whole day, not at once.
But what is the dose someone would expect a cholinergic crisis to occur, I wonder.