BBT Chart Help!!

​Which one should I go by for DPOs? FF has CD 19 marked as O day but says it could be a fluke since the time taken wasn't quite the same. Kindara has CD 16, even though pos opk wasn't until CD 17 (BUT I was only talking an opk once a day instead of twice because my windowis short and that was the first day using digital to be clear since I was having a hard time reading the lines on other tests)