So we have MS 365 Family. Right now, three of us (Mother, Father and Daughter) are using it, each with one of the six subscriptions on his or her separate PC (and on lots of iDevices).

So, Daughter's PC has her MS 365 subscription, but Father is also a user account (not 365 account) on that PC as administrator of that PC. Can Father now activate his existing MS 365 subscription as a user on Daughter's PC without using up another of the six MS 365 subscriptions?
if yes, Father's MS 365 subscription would be activated on both his own PC and as an admin user on Daughter's PC, and Daughter's MS 365 subscription would be activated on her user account on her PC .

Do I have that right?

Thanks.