Does your OPK get darker and darker leading up to your peak?

I had a decently dark test (not peak yet) and then lighter the next day. Around the same the next day. And then a little lighter the next day. And it’s even darker today then it was the first day (still not peak yet) so I’m just curious if it’s all over the place or does it need to get darker and darker each day? Is peak close? (App says ovulation is in 2 days)

All tests are taken during the same time every day.