Custom approval rule that automatically approves the forecast if the EAC and ETC values unchanged

Summary:

Hi Everyone, 
We would like to implement a custom approval rule that automatically approves the forecast if the EAC (Estimate at Completion) and ETC (Estimate to Complete) values remain unchanged. If either of these values changes, the forecast should be routed for manual approval. To achieve this, we have defined the following logic:
Logic 1:
If the current EAC equals the previous EAC and the current ETC equals the previous ETC, then auto-approve the forecast.
Logic 2:
If the current EAC does not equal the previous EAC or the current ETC does not equal the previous ETC, then route the forecast for manual approval.