Interesting how people's experiences vary. I run feeders exclusively; several mechs, a DNA30 and a DNA40. All of them use 18650s. The 40 is the only one on which I can consistently drain a whole 6ml bottle on a single charge.I must say after using the dna-40 for a while now I've come to realize two things.
A) it burns through batteries like there's no tomorrow
B) I do see a few benefits over the mech mods in that you have the ability to "fine tune" your vape and find the sweet spot of your liquid. With duals metered at 0.35 I get a great vape at 29W but if I bump it up to 31.5W I get a stellar vape. I guess this ability to find the sweet spot is an arguable benefit. However you sacrifice battery life because at that wattage my batteries drain 20-30% faster at least
Are you running your 40 Temp Limiting mode?