OPK accuracy and tracking...

I bought the wondfo strips this month and noticed women tracking their ovulation on paper...so I’ve decided to give that a try too...however, I’m a little confused on the accuracy. After 5 min the strip is done. Don’t look at it, throw it away, whatever it may be, the testing window is over.

So my question is, why should I keep tracking it this way when obviously yesterday’s and today’s AM test are now completely invalid and look darker than they once were in that 5 min window. When I look at it I’m looking at inaccurate data. Should I just not be tracking ovulation this way?

And yes, this is operation ovulation.