Frame data question

I’m trying to learn how to better understand frame data in combos. I’m going to use the beginning of Juilia’s 20 trial as an example. St. LK + St.LK + raging rapids. St.Lk has +6 frame advantage on hit so I figure the reason the second St.lk connects is because it has 5 frame start up and hits on the 1st active frame which is the 6th frame. Now my question is why does the first half of raging rapids (back+MP) connect after a St.lk when (back+MP) has 6 frames start up before going active?

Hi I’m a Tron main and what is this

Uhhhh bro Cross Tekken is this way >>>> http://shoryuken.com/forum/index.php?forums/julia.440/