DSF

i have upped the time now to 230 seconds from 180 and have done 2 mugs both look good ....so am thinking it needed longer.........i have noticed the edge of the paper that sticks out over the mug started to go brown (i could smell it) so maybe i should wait for this to happen then i know its had long enough to heat up??

As it seems to be a fixed temperature press I'd find the minimum time needed to produce a consistently good result and go with that.
Any longer and you'll be wasting time and electrickery.

Mark