NavyLCDR said:
As long as the computer has a digital entitlement for Windows 10 stored on Microsoft activation servers, any number of Windows 10 insider installations of the same edition will activate on that computer, along with the original Windows 10 RTM.
That's my understanding also. From what I seen posted here and on other forums. Switching from Consumer to Insider is just a Settings change so It doesn't make sense for it to lose activation in the process.