I'm 'upgrading' to a Legend R7 in my home (want to keep the ATL sets). When I calculated the unit loads, I've always exceeded 54 (391C power). I calculate the unit loads for the board types and the number of phone types, adding the numbers together. Since this is in a residence and no ore than 2 or 3 phones would be used at the same time, is the actual count of the phones that important? Or should I add the Aux Power? I'm also using the expansion cabinet for all 016 T&R w/ Ring Boards (5). I have a large collection of single line sets on display. So since none of these sets really draw power or are used (except maybe 2 at time for demos); is calculating the load units for these to determine if an Aux Power would be needed necesary?