You know, yes, you can't exactly compare 1 to 2 battery mods in terms of life. There also enters the question of how efficiently battery discharge is converted by the mod's board to wattage. I have some batteries that are kind of "battery hogs" and others that just seem to conserve battery life far longer. This can be added to or subtracted to in all sorts of ways, some mods will essentially "turn themselves off" if not used in a specified period of time, and that can make a difference. Mods with extensive displays and/or things like clocks, whistles large color screens and etc. can also make a difference.
I'm not saying your Smok mod has all those things, my guess is, Smok being smok, they may not have the most efficient board on the market, in fact I very much doubt they do, so if you like this mod, you really want to consider which battery is going to suit it's (and your needs) best. I'm not saying it's a bad mod, but it may be a mod that drains hard and fast, and you may want to look at what battery would suit that application. Maybe.
Anna