Digital vs. standard OPK test results

Hi all!! I have been TTC for a year now and have been testing with regular opk strips for about 8 months. I just bought a digital pack because I had run out of the other strips and didn’t want to miss the window.

Had anyone else experienced VERY different results between digital and manual strips? For example, I was seeing on average ovulation around CD 12-13 and now I’m on day 16 and still getting negatives on digital.

Would love your thoughts! Thanks in advance, friends. ♥️

(Additional background: I was tested for AMH levels and I’m at .8; I also had an HSG last week so I’m hoping that potentially “cleaned the pipes” to make way for the swimmers 😂. I am 38 TTC 1st baby and my husband has two kiddos from a previous marriage/my bonus sons)