I have a WOWTAC A2S.

Here are some shots of the light output PWM at different levels.

Moonlight

Low

High

Turbo

Looks like Low – High uses a 15.2KHz PWM and increases the duty cycle as it gets brighter.
Moonlight and Turbo I see no PWM.
I (assume) Turbo is a constant current affair as opposed to running flat out.
I’ve not tried to get inside so I have no idea how easy it is to mod.
Hope this helps.
All the Best,
Jeff