I'm currently posting this with TornTools enabled.
I was attempting an Arson Job and managed to stoke a fire twice at 99% yet it failed to reach 100%
The Hydrogen brought it from 95% to 99%, I then used the Methane and Oxygen after that point yet it stayed at 99%.
With the amount of spread of the materials used, shouldn't it have reached 100%?
If this is normal behaviour then I apologise even if it personally does not make sense to me.