Quick take on NIH point scale: will this shift budget uncertainty to the NIH?

Just heard about the new NIH point scale, and was puzzling through some of the implications. First, quick summary: NIH, in an effort to split the pie more evenly, is implementing a system in which each grant you have is assigned a point value, and you are capped at 21 points (3 R01 equivalents). Other grants are worth less. The consequences of this are of course vast, and I'm assuming most of this is going to be covered elsewhere. I'll just say that I do think some labs are just plain overfunded, so this will probably help with that. Also, it's clear from the point breakdown that some things are incentivized and disincentivized, which probably has some pluses and minuses.

Anyway, I did start wondering about what life would be like for a big lab working with 3 R01s. One of the realities of running such a lab is budget uncertainty. I remember early on when I started at Penn, a (very successful) senior faculty member took me to lunch and was talking about funding and said, "Jeez, my lab is too big, and I've been thinking about how I got here. Thing is you have a grant expiring and you want to replace it, so you have to submit 3 grants hoping that one will come in, but then maybe you get 2 or even all 3, and now you have to spend the money, and your lab gets too big." Clearly, this is bad, and the new system will really help with that. I guess what will happen is that if you get those 3 grants, then you will only take one of them. And, you may have to give back the rest of the grant you already have so that you don't go over 21. Think about this now from the point of view of the NIH: you're going to have money coming back that you didn't expect, and grants not funded that you thought would be funded. The latter is I suppose easy to deal with (just give it to someone else), but I wouldn't be surprised if the former might cause some budgetary problems. Basically, the fluctuations in funding would shift from the PIs to the NIH. Which I think is on balance a good thing. It makes a lot more sense to have NIH manage a large pool of uncertainty in funding than to have individual scientists try and manage crazy step function changes in funding, which will hopefully allow scientists to have more certainty on how much money to expect moving forward. Nice. But maybe I haven't thought through all the angles here.