Symptoms
Provider creates new tax in PBA-E CP > Home > System > Settings > Taxation
with the following settings:
1) Calculation Level Level 1
2) Calculation Type Calculate Per Document
3) "Extract Tax Amount from Item Amount" enabled.
On pressing "Save" the following error appears:
"Extract Tax Amount from Item Amount" flag may be applied to the 1st level and item-based taxes only.
What is the reason for the error?
Cause
In current product implementation "Extract Tax Amount from Item Amount" feature is not supported for tax calculation "Per Document" type. The feature request with ID PBA-58102 was submitted to implement such functionality in one of the future updates for PBA-E.