It will go to 29.8w (3.86v). BTW, the amp limit is not 6 amp. The voltage limit is 6v.
I don't like it at that wattage. At 20w it is cool, 25w it is getting warm. At 29.8w it is too hot for me personally. I can tel the difference between it at each of those power settings and between them.
It will only let you set it to it's minimum or max power, won't let you go higher or lower. If you are calling the eVic Supreme a semi-smart device compared to a Provari as a smart device, you might want to go read up on it a little more. The eVic-S will actually learn how you vape (wattage, duration of draw, etc) and dynamically show remaining usage based on the settings you have dialed in. It can be programed to ramp up and down power through a draw.
Right now my guess would be the over temp protection kicked on, since that is the only thing that should have forced an immediate shutdown.