Pre tax and Post tax for commuter benefits

Summary:

Show Pre-tax and Post-tax values based on a limit for commuter expenses

Content (please ensure you mask any confidential information):

We have setup the Commuter - Parking and Commuter - Transit plan. The employee can elect upto 500 usd per month, out of which 325 is Pre-taxed and anything over and above that is post-taxable. We tried the configuration using the Variable rate and it does not work. Is there a way to deduce the values using fast formulas and in the first place, is it feasible?

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