The slits on the T3 is U-shaped which need the additional 2 "flavor wick" to plug the gap to prevent flooding. Below is a pic of the side view (showing the slit) to give you an idea of what I'm referring to:And for the people who have mentioned the second wick... is there another one that is not visible without taking it apart? I just need to take it apart when I get home from work I see...

The blue circle represents the main 2mm wick (blue) which is coiled whereas the "flavor wicks" (red) are just strands taken from a silica wick to lay on top of the main wick (not coiled). There are some gaps (within or between wickes) to allow the eliquid to flow to the coil but too much gap leads to flooding and too little leads to dry hits. Also the number of air holes and the viscosity of the eliquid comes into play; 2 air holes and higher PG% eliquids tends to flood easier than 3 air holes and higher VG% eliquids.