In the case of severe undervaluation/underpayment beyond a few cents (which would only happen with the haircut, as @blocktrades stated), it is my opinion that a lot of proposals would absorb it for a limited period, but would then either request additional funding or cut service/spending in some manner. I could be wrong, but that's how I see it, and I think the current situation is pretty similar. Proposals have been overpaid for a month or so, and it was overlooked/absorbed as a market fluctuation, but at some point it does become too significant to ignore.