After an acquisition, do you lift people to the range minimum at once or in stages?

We have just integrated a 320-person business into our structure. I work for a building products manufacturer in the US, about 4,700 employees in total. Of the 320, 74 are below our range minimum, by an average of 7% and a maximum of 22%.

Bringing everyone to minimum on day one would cost about 410,000 dollars a year. Finance would prefer to phase it over two review cycles. My worry is that these people will be able to see our ranges from the first week.

What have others done, and did phasing cause problems?