True on both fronts.
One of the issues with the Chinese “40W” lasers is that usually represents the maximum power output of the tube. To get that you actually have to overdrive the tube. Combine that with the inability to actually measure the output in real time and the lack of calibration on the power controls and it’s easy to burn out a tube. My K40 actually has a 32W tube for example.
Sometimes you’ll see the tube marked as 40/50 or 100/120 which gives you running rated power & maximum output when overdriven. So my K40’s tube should be marked 32/40 but the machine’s seller says it’s a 40W. Not entirely untrue but somewhat deceptive.
Running a tube at maximum or “100%” power will reduce the lifespan of the tube vs even 95%. So some lasers allow you to set governors to prevent running them too hot. The K40s generally don’t have this feature and you have to be careful not to dial up the power too much.
GF takes this into account and “Full” power is the full normal operating power - you can’t overdrive the tube and it’s something less than 100% power per Dan last year. We shouldn’t see any reduction in lifespan by running at Full power. The 0-100 scale is used to provide settings compatibility between the Basic and the higher power (45W) Pro.
There is some misperception that Full = 100% and 100 is therefore really 99%. In reality it’s some other value but that means Full on the Basic = 40W safe maximum and Full on the Pro = 45W safe maximum which means the difference between 100 & Full on a Pro is a larger power jump than between 100 & Full on a Basic.
In practice you don’t need to worry about how many watts of power (or %) you’re using - just keep track of the ordinal settings and let GF take care of translating it into delivered power.