Could someone tell me the effects of waking up while you are sleeping? If i happen to do WBTB on a regular basis, but am increasing the amount i sleep, is it still the same amount?

Last night i figured that i was getting about 12 hours of sleep, with a WBTB in the middle. If i subtract 1 hour, WBTB method, would it be the same as 11 hours of sleep? Does waking in the middle of the night effect my hours if i am actually sleeping more?

My deep sleep isn't being taking away from because i am sleeping for about 5 hours before i wake up.

If there is a post on this just give me a link and ill delete this post.