I used the UCM to count my toys while at the same time using my own method. I no longer use the UCM though.
If a Toy has sentience it's counted as 1 as in headmasters (Hasbro - not that I own any) or targetmasters. Drones don't count as 1, only their control bot as in PCC.
ROTF Devestator (supreme not legends) count as 1 even though each vehicle has it's own name. They don't have their own robot mode.
For me Headmasters and Targetmasters (and any other of that evolution) always counted as 2 as their partners had their own personality while Targetmasters had their own alt mode that didn't need the main bot like the Power/Headmasters did. Yes they are just a gun but so was Megatron.
Pretenders count as 1 but Actionmasters count as 2.