Stop. You cannot SLAM with test strips. Period. There's a reason the SLAm article lists as FAS-DPD tester as a prerequisite.
Using test strips, you're working practically blind. At high FC levels, the color pads will bleach out, so even if they were accurate in the beginning they still wouldn't work. Try to paint a picture in the dark. Odds are you'll get paint on the canvas but it won't look like what you wanted. All you'll have done is make a mess and waste paint. Chlorine is the paint and the pool is the canvas. The test kit is the light you use to see by.