Purchase Order Tax Calculation for Recovery and Non-Recovery Tax

In EB Tax we have the Recovery Rate which was 100 and we change to 0.

Now Purchase orders were created with '0' recovery rate and we have reversed the Recovery rate to 100. Now when we matched the Purchase Order to AP Invoice it is calculating Recoverable Tax, Non-Recoverable Tax and Tax Rate Variance for the purchase orders which were created with '0' recovery rate. Do we have a solution or workaround to fix this. We have Open Purchase Orders for which Partial Invoicing has been done, can we change the Recovery rate to these Purchase Orders to 100%? Please advise