So my doctor explained it this way to me...
Since I have pcos my baseline lh level is higher than most woman. Pre-surge, woman have an average lh level of 1-20 or even 30 mi/u (or whatever the unit it) and since I have cyst that are always producing estrogen, my body creates more LH in response. She explained to me that the 20 mi/u opk are too sensitive for me and will probably always shoe up positive. Once the femara kicks in, it will lower my estrogen and stop the production of LH and begin producing more FSH to grow my follicles. Long story short, it will just drive me insane to test to early with a high sensitivity test.
P.s.
On the same day I took that IC opk and it came up positive I used a CB digi to try and confirm, and the second line was nearly non existant. The CB opks are 40mi/u which is great for any woman with a high LH baseline