When you have multiple state employees you need to enter the State Tax ID in the State Tax records that are attached to the employees. And as you found out, you do need to select the employees by range which is why it is a good idea when setting up a multi-state system to use unique Employee ID's such as CA-0001, CA-0001, WA-0001, etc.
Unfortunately it is a caveat of multi-state companies. And every time you update PayWindow, you need to remember to re-enter the state ID's in the state tax records used.
ZPAY Payroll Systems, Inc.