And again, on field is not the same as on paper, things don't always go the way you would like to, and you end up with situations like this pretty often, you CAN'T make everything work perfectly all the time, especially as Sub. Being a Sub player since late Wotlk and for having played it for the whole Cata expansion, I have to say that Sub rotation is a lot of improvisation, as there are a lot of factors that can screw you rotation, if you plan to follow a strict set in stone rotation, then you'll fail at playing Sub. You simply can't anticipate everything that will happen in your Sub rotation, you can't know if in 43.7 sec you'll end up with both SnD/Recup falling off at the same time with enough CP to refresh both, that's impossible.
If you don't play Sub by yourself and train on the rotation and maintaining the whole buffs/debuffs, if you only follow what's written on paper and can't react to unpredictable behaviors, then you'll do bad DPS, and you're better go with Assas/Combat spec, if you want something set in stone and easy to follow.