5 or 6 DPO …?

Susanna

Attaching a picture below of my Premom app with my ovulation test. It is saying my peak is CD19 which would make me 5DPO today… looking back at the chart, my levels were the exact same the night before. If I counted my peak as the day before, then I would be 6DPO instead of 5. Can someone look at this and let me know what they think? Thanks in advance since this is my first month using Premom & the app!