Whoops. I was looking at level 4.

The point still stance, for the 5MWD not to be an issue, the entire xp budget needs to be usable in one single encounter with no pulling of punches by me. So at level 5, that means 14000xp in one fight.
What that means is that I have to be able to use a Beholder and 9 Ogres or M mummy lord and Something else or an Adult Black dragon and a hundred or so Kobolds. By the rules I could use all 1250 kobolds to flesh out the last 2500xp since their CR is significantly below the average CR of the monsters in the group, but I think 100 with an adult black dragon is sufficient to TPK a 5th level party of 4.
There's no way for me to hit them in one encounter with the full daily budget(or anything close), which is necessary for a 5MWD environment.
Yes, of course they aren't talking 5 minutes. It means that you can fight, rest, fight, rest, fight, rest, and so on. Since the group can decide to go rest after a single fight, one fight needs to be doable with the full daily budget.