Good question. LOLA lot of the claims for 18650's seem to be fairly imaginary, the 'standard' sort of rating is about 2.6Ah.
Have you done nothing to reduce consumption?, other than remove the unwanted power LED?.
I have done some, as mentioned in previous posts, which gave additional battery life and need to learn more to try to increase that.
It is to be my next step. Just working on the powering of the device at this time.
For one thing, I think it may be the transmission power consumption that really sucks it up.