Surefire KL1: poor efficiency?

Over time i got the impression the KL1 isnt such a great performer regarding efficiency. I decided to compare the flashlightreviews numbers against other common lights:

single cr123:
Fenix P1:
1:47 x 2800 'output units'
vs 1:30 x 2000

two cr123:
Inova X0:
5:40 x 2400
vs 2:50 x 2300
(here the KL1 really stinks)

Maybe the buck/boost capability was a bad compromise... i think its sad that surefire cant do better

The buck/boost that Surefire uses really uses a boost circuit with a small modification. That modification (cathode referenced to B+ instead of ground) costs about 20% or more in efficiency over a good synchronous buck/boost circuit. The KL1 circuit is probably 5-6 years old and Surefire just never upgraded it.

There are several synchronous buck/boost controllers with the four FET topology that seamlessly transitions from buck to boost that no one seems to be using except the shop. These are the best in my opinion. I know TI and Linear makes them and there may be others as well.