Starting January 1, 2019, the new WA tax will be implemented based on this article: Washington Paid Family and Medical Leave (New Tax 2019). The part where you need to go to each employee tax setup to enter the percentage of the total insurance premium is tiresome. I understand that you don't have so much time to do it if you have more than 50 employees. However, for now, that's is the effective way to update the new WA tax law.
Let me go ahead and send your feedback to our product development team. They might consider adding some ways on how to enter the percentage to the employee's profile for QuickBooks Desktop users.
Don't hesitate to post more questions. We'll be here to help.