Take the money and run!!!! In the short term, the very underpaid will get some relief. In the long term, it will NOT effect your negotiations in the least bit. Mismanagement will drag their feet until someone puts a gun to their heads to a contract done.
I am speaking from prior experience at 9E where they tried the same thing. At the time I was dead set against it even though I would have gotten the raise. Looking back at it now, I should have taken the money and ran. Forcing 3 more years of poverty wages did nothing to speed the process of the contract and people were still lining up to take our low paying jobs.