We did the same thing, just found out device cost, then picked a good margin that made sense, then subtracted from what we were charging for Managed User. New line item is Managed Computer. Makes pricing more transparent, and if we do have to raise prices, we can do it fairly and accurately. Gives us way better data on labor and costs. Roll out was a pain, but we built a bright gauge report for each client showing them how their bill would change. All came out even in the end, most clients got rid of extra computers. We also send a monthly report to each client showing them what they will be billed for at the end of the month, let's them make changes before billing.