Got my MF01 - stepdown question

First of all, the light output on Turbo is nothing short of amazing. Lights up the entire neighborhood.

But here is the querstion:
How quick is this supposed to step down?
Playing with it outside, I was getting a six second stepdown from Turbo
Let it cool off a bit, stepped down in 15 seconds.
I know this thing is a battery killer, but that seems very quick
I am using new Samsung 30Q INR batteries, and I can keep bringing Turbo back up.
Just wondering if the stepdown is timed or heat based?
Can 8 seconds be normal?
Update: Let it cool off, stepped down at one minute on the mark, and it was getting too hot to hold so I guess it is thermal.
I ordered the extension tube, but I suspect it would not extend the Turbo time since the heat sensor would be the same.
Anyone using the extension tube?
Someone mentioned it is parallel, I don’t see how that can be since it is an add on cartridge, but what do I know!

This is what i got for my MF01 prototype with new long tube.

Interesting. Does not look like much difference. I was getting 60 seconds from cold with the standard tube. Looks like you dropped off at around 67 seconds.
Is the second battery carrier in parallel? How do you do that?

stepdown is heat based… mine steps down after like 60 seconds or so i think. I think its a good light it can manage highest output ok considering its a budget light. If the head was bigger with deeper fins it would manage heat a little longer tho.