Adding devices for Power Management

Running OME 4.5.1 - servers are 14th generation

I have a R640 that is showing up under idrac Servers, and I am able to enable Power Management - meaning it is showing up under Individual Device in Power Management.  I have (2) R740XD's and a R740XD2 - these are correctly being discovered but I can't enable Power Management on them - (they are not showing up as available in Power management).  They are all running the same idrac firmware and everything else with the 740's seems to be discovered correctly.  Am I missing something simple?  I did not do anything different with the R640 - it is just working.