My LH surge Question (didn't want to hijack the other thread)!

I started using the Oracle OPK's this cycle, and started testing on day 9 (i'm roughly a 25 - 26 day cycle) and used them for 4 days (testing at 2pm & 8pm respectively). On the 2nd & 3rd day of testing I got a VERY feint line, then on the 4th day I got a test line nearly as dark as the control line, but then on day 5 (of testing) I didn't get any line!

About 2 days later, I decided to test again, purely out of curiosity to see what'd happen, and I got another very feint line.

Do you think even though I didn't get any line the day after I got the darkest line that I still should have been testing following it? (meaning I would have been using the OPK's for up to 7 days?)

In my opinion I just think that seems very long, in comparison to how long the websites suggest testing for.

Keeping in mind I have been known to have a very short luteal phase... if that helps any..

Any help greatly appreciated!