Compare OTO and Taylor results for free chlorine

My old PS-200 kit seemd to be giving quite different free chlorine results than the Taylor 2006 kit I bought last July. So I bought a new HTH 3-way kit at Walmart. The Taylor drop test shows 3ppm, and 0 combined chlorine. The OTO kit says 5-10, and is on the darker side, i.e. 7 ppm. Did the tests again to make sure.

Can't really use the OTO kit if the results are THAT different. Is something else going on? pH results are in line with each other, ~ 7.6. CYA is 100.

Bill.