Comments
Option to recognize the withholding tax payable GL entry at the time of invoicing should be available. It is required in the Philippines to record and deduct the withholding taxes when the purchases become payable. In addition to this, option to make necessary adjustments for the posted withholding tax during invoicing should be available. In this way, the user who will create the actual payment can review the posted withholding tax and adjust if needed.
This should be an automatic input.
When entering a Sales order, the "Sales responsible" on the sales order will be the "employee responsible" on the customer account.
If the employee responsible is meant for another function then there should be space to hard code the Sales Responsible against the customer master record. Otherwise the administrator has to open the customer record to find this information.
The current approach with the sales unit being price-sensitive is a good approach to persuade customers to buy full packages.
Still, your idea is good to reduce the management work of trade agreements and the risk of functional inconsistencies when above scenario is not desired by a company.
Therefore, I believe there should be a parameter to switch between the two logics, such as an "Allow unit conversion" checkbox in the trade agreement journal line details fast-tab, which will be considered by the "Find next" checkbox.