Thanks for joining this thread, @olduser. I understand what you're going through and I'm here to help ensure you're able to update the Washington workers comp class. 

As a workaround, we can force the system to re-order the rates and use the most recent effective date for current paychecks. You'll want to follow the steps beelow to resolve the issue. Here's how: 

1. Go to the WA Workers Compensation Tax Setup page.
2. Click Edit next to the Class, then delete the most recent rate (this is the rate on top of the list).
3. Click OK, then click through the steps to Continue and allow the system to recalculate and create adjustment checks.
4. Go back to the WA WC tax setup page, then click Edit next to the Class.
5. Add the desired rate back in with the correct effective date, then click OK.
6. Click through the steps to Continue and allow the system to recalculate and create adjustment checks. 

Once done, run a test check to confirm the rates have been corrected and that 2020 checks calculate correctly. 

For future reference, read through this article: Washington workers' compensation setup and calculations. It helps you learn about setting up and calculate Washington Workers' Compensation.

Feel free to message again if you need further help. I'm always around to listen and lend a hand.