Luteal phase BBT ?

Becca • RN, mama to two daughters, recurrent pregnancy loss survivor, 🌈 baby # 3 on the way
Curious if anyone knows whether BBT will rise steadily during the luteal phase if conception has occured or it it will stay above the coverline but fluctuate? 
​My temps been 0.7 - 1.0 above coverline for 11 days but has not been gradually increasing (or decreasing). It's fluctuating. 
​I'll know in a couple days whether or not this is a good sign if AF shows, but just curious if anyone knows.