Sounds like it - the tailcap is double spring where the driver side is a single (albeit shallow) spring. By bypassing it or doing a double-spring mod you should get more light, but it’ll just heat up faster, and not be super noticeable anyway.
Looking at TA’s XPL HI review, it seems that going from 4.5A to 5.5A is only ~ 160 extra lumens, or ~11% more (that’s on a CW emitter) - only slightly noticeable. But going from 4.5 to 5.5A on a flat white, it looks like you actually lose about 40 lumens , or around 4.5%.
Either way, if I can hit 4.5A consistent with a flat white, I’m happy 
and with Anduril, I’ll be far happier than with any of the UIs I’ve found on Convoys so far.