I've used the Advanced Clear Blue OPK for 2 cycles now and got different results with both cycles. My first cycle I got High Fertility readings (flashing smileys) for Days 11-17 and the finally got a peak reading on Day 18. The next cycle and I got low readings on Days 13-14, and then a peak reading (solid smiley) on Day 15. The test instructions said to use FMU so that's what I did, but I'm wondering if I should not have been based on what I have read on these posts?

I'm wondering if I should try a different test? Or is this normal to get such different results each cycle? I have very regular cycles so I'm not sure what to think?