Have you always only gotten 2 sessions? (more typical would be 4 ... or maybe 3). Or is this with a depleted battery?
The battery has def got slightly worse over the years - however, most of my sessions I usually take a break after every few hits, meaning the crafty turns off and temp reduces, then to get it back up to temp for your next hit it takes more battery power. I'm sure I could get 3 sessions if I had a solid session - but I like to chill and not rush it.
this is the only part in your for the rest good tips for usage ,that I strongly disagree with.:
never ever blow in the bowl!
Fair play mate, the blow is usally after I have dumped the bud, banged upside down then a blow after - I'm not sure if a light blow to a empty chamber is any worse than packing down the bud when you load it - either way, I'll get rid of the blow ha