Which dpo is correct?

Question

So according to period tracker I am 9dpo and with glow I'm 7dpo. I don't track with strips. Both have my af due day for next week Thursday. Which should I listen to or should I just say 8dpo between the two?

Answer

So this morning I got a faint line

Answer

I ovulated the 28th this month which means I’m 8dpo my period are due next week Thursday as well.

Answer

Same thing with my two different apps. Both predict same day for AF but they have O off by one day.

Which dpo is correct?

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