I think Jorge Cerventes invented the grams/watt measure (maybe not but that's the first place I read about it) and to an extent, it's a nice way to measure efficiency. It's also a stupid way to measure our dicks against one another as something as simple as hood design can have a substantial affect on yield.
Perpetual or not, no one has ever included their vegging wattage in the grams/watt figure, seriously. If I vegged with a 1000 and flowered with a 400, am I expected to yield 1400 grams from a stationary 400 watt lamp?
Anyway, yield is dependent on a lot of different things so to sit here and say I'm better than you or you're better than me and base that statement on yield is just stupid. What we can say in regards to yield is that doing this or doing that had this affect on yield (when growing cloned strains in the same place in our room every time). That's what I do in my journals. If someone really wanted to increase their yields, look into canopy management.