I don't know why.. but when I pre-fill carts with syringes or the paperclip trick (see intro to vaping video around 17 min in I think?) and I let them sit for a few hours.. they last much longer than if you just top off (4-5X as long!)... also.. puff out the stuffing a little so it is not recessed too far into the cart and it wicks the atomizer better.
This is why I put the drops in, then the filler, then top off with drops.
People talk about getting 11 - 12 drops into a 901 cart but I can get 8 - 10 into a 401 cart.
MAAAAAAHAHAHAHAHAHAHAHAHAHA!!!