I can only speak to my experience with this sort of thing.
I need a good throat hit (TH) to be satisfied and if a particular flavor doesn't have a good enough TH I have to take longer draws. It could be that the Cafe Mocha has a better TH than your other juices. Flavor is a contributing factor as some flavors give a bigger TH than others. Cafe Mocha was one of my favorites. I also really like the mint/menthol flavors because they give a great TH. So does cinnamon, like cinnablaze.
Higher voltage and lower ohms will also give more TH. The tanks come with the 1.5ohm DC cartos, that should definitely up the TH. I personally didn't like how the low ohms (I prefer high ohms, like 3) changed my favorite flavors and gave a warm vapor. However there are many people that love those cartos, so I'm not saying they are bad, I just don't like them. That could also explain why you like the Cafe Mocha, they come in wow cartos which are 2 ohms. The cool cartos (premium flavors) are 3ohms. 3ohms on a stick batt will give you the least TH (not counting all other variables of course).
When I had this issue higher voltage really helped. I used the 3ohm cartos on a 5v passthrough (PT) and it was very satisfying. Also a 2ohm carto on a regular battery did the trick. But the PT was my favorite. I saw you post on the thread about the DAV. Those along with the Zeus are my preferred vaping devices nowadays. The Zeus gives the same 5v as the PT but I don't have to be near a wall outlet to use it. The DAV allows me to use whatever voltage works best for the particular flavor/device I'm using. If you've never vaped at 5v I'd recommend giving the DAV a try. If you don't mind the larger size of course. They are much larger than a regular cigarette, they are more comparable to a cigar size.