Yeah, something i've been wondering since I first started looking into them too. At first i thought "well, its probably because hot air rises and the vaporizer needs to make use of that to keep the herb heated right?". But when i found out thats not true i was like "wtf then? havent they heard of gravity?". One of the main reasons i got a DBV. But even having it level isnt enough sometimes, so i traded in for a SSV, and i dont feel at odds with gravity and physics every time i vape now.