Due the variances that all salt tests have, they may be off in opposite directions. Say, the cell reading high and Taylor reading the low end of range.There is no subjectivity with the K-1766. Why wouldn’t one rely on it?
When they kinda agree it's great but when they don't you want multiple opinions so that hopefully a couple of them agree. Say, the cell, Taylor, 2 pool stores and a handheld salt meter.
I wouldn't think to add one bag of salt per Taylor, but I wouldn't cut out my flow switch or replace the cell with only Taylor.