I have the lavabox dna 200 900mah battery, not very happy with the vape time about 7 hours in temp mode at 40w. Have ordered one of the "wismec-reuleaux" from joyetech UK should start sending out 9th November, £170 with three 3 VTC4s
My lavabox battery life is very similar to yours, Ti .2 ohm coil- 40W- 430f i get about 7 hours use. I have ordered one of the Reuleaux mods to improve the vape time.