5%'s do add up to 100%, eventually 
. This is what we do, little by little, with heavier wires, copper braiding springs, better cells, better thermal treatments, copper MCPCB's, higher bins, AR lens, centering/focusing emitters, etc.
It's all about efficiency - getting the most out of the parts. There's trade-off's of course of cost/looks/functionality vs efficiency.
If I had a really nice light but with a big black bezel, I'd think about grinding it down, removing the anodizing, polishing up the aluminum. Of course with a SolarForce, you always have the option of buying their low profile SS bezel.
Edit: Finally found it! Here: https://budgetlightforum.com/t/-/19458
I really have no reason to doubt these results - they seems very thorough, and lots of repeated tests. Basically he shows about a 4% improvement between the stock L2T bezel and the B6 SS bezel (here) - the two I tested.