This scenario has been playing out form a long time. To me, it was a simple business decision.
So, I would put it wherever they wanted, with the appropriate disclosure regarding the change in the contract, make sure I also still included the analysis of the contract in place on the effective date, update the signature date, and move on.
Others are free to take another approach. Some do draw a hard line that page 1 of the URAR is somehow sacrosanct and not to be changed. I never understood that, but to each his own.