The Lume X1 in the KR1 is a fantastic driver but I doubt it’s 33% more efficient than the SC65C. We do know that the 719A is a relatively inefficient emitter (even less than the 519A) and Noctigon says the NTG50 puts out significantly more lumens than a 519A in the KR1, so it’s likely not an apples to apples comparison. A pretty common complaint about the SC65c was that the move to 719A greatly reduced the output.
I’m also curious if you would be willing to do a test of one of the non-PID modes. Zeroair has the only SC65C runtime test I can find so that’s something we can use as a comparison point. Annoyingly, he used a 2000mah cell instead of a more standard one, but you could compare to his test of the top non-PID mode (244 lumens) and see how it matches up to ZL’s promise (3.5 hours) and Zeroair’s test (2.5 hours on 2000mah).
I don’t have the capabilities to do runtime testing and have never used my sc65c for an extended duration.
Maybe worth messaging ZL to point out this thread?