Have you recently added salt?
Normally we see the salinity reported by the cell to be less than the Taylor test or strips as the cell ages or as the cell accumulates scale.
The Taylor K-1766 test kit can be tricky but is accurate to within +- 400 ppm.
Part of the difference may be testing error.
Water sample size is only 10ml.
Be sure to add the R-07018 regent until the sample turns milky red. The color of the sample will be like a weathered brick. This normally takes a few more drops after the sample turns light milky pink. If the sample turns brown then you have added too much silver nitrate and are past the endpoint.
Warning: If you get the silver nitrate on your skin it will not wash off. It will take a couple of days to wear off.
For version 1.5, be sure the Aquarite is set for the correct cell size in the setup menu.
If the green generating light is on, then I would not add salt.