vendor_payment_diff_amount/SCENARIOS.md

Payment Scenarios with Deductions

This document explains how the module handles different payment scenarios.

Scenario 1: Payment WITHOUT Expense Account

When you create a vendor payment without setting an expense account, the system uses the standard vendor payable account.

Example:

• Vendor: PT Telkom Indonesia
• Amount: Rp 2,000,000
• Deductions:
  • PPh 21: Rp 100,000
  • PPh 29: Rp 50,000
• Final Payment: Rp 1,850,000

Journal Entry:

Account                              | Debit           | Credit
-------------------------------------|-----------------|------------------
Accounts Payable - PT Telkom         | Rp 2,000,000.00 |
PPh 21 (Tax Payable)                 |                 | Rp 100,000.00
PPh 29 (Tax Payable)                 |                 | Rp 50,000.00
Bank Account                         |                 | Rp 1,850,000.00
-------------------------------------|-----------------|------------------
TOTAL                                | Rp 2,000,000.00 | Rp 2,000,000.00

Explanation:

• The Accounts Payable line uses the vendor's payable account (from partner configuration)
• The payable account has the partner_id set (PT Telkom Indonesia)
• This is the standard Odoo behavior, just with deductions added

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Scenario 2: Payment WITH Expense Account

When you create a vendor payment with an expense account set, the system uses that expense account instead of the payable account.

Example:

• Vendor: PT Telkom Indonesia
• Amount: Rp 2,000,000
• Expense Account: 611505 Telepon & Internet
• Deductions:
  • PPh 21: Rp 100,000
  • PPh 29: Rp 50,000
• Final Payment: Rp 1,850,000

Journal Entry:

Account                              | Debit           | Credit
-------------------------------------|-----------------|------------------
611505 Telepon & Internet (Expense)  | Rp 2,000,000.00 |
PPh 21 (Tax Payable)                 |                 | Rp 100,000.00
PPh 29 (Tax Payable)                 |                 | Rp 50,000.00
Bank Account                         |                 | Rp 1,850,000.00
-------------------------------------|-----------------|------------------
TOTAL                                | Rp 2,000,000.00 | Rp 2,000,000.00

Explanation:

• The Expense Account replaces the payable account
• This allows direct expense recording without going through payables
• The expense account still has the partner_id set for tracking
• This is useful for immediate expense recognition

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Key Differences

Aspect	Without Expense Account	With Expense Account
Counterpart Account	Accounts Payable	Expense Account
Account Type	liability_payable	expense
Partner Required	Yes	Yes
Use Case	Standard vendor payment	Direct expense recording
Payable Created	Yes	No

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When to Use Each Scenario

Use WITHOUT Expense Account when:

• You want to track vendor payables
• You need to reconcile with vendor bills
• You're following standard AP workflow
• You need aging reports for vendors

Use WITH Expense Account when:

• You want immediate expense recognition
• You don't need to track payables
• You're making direct payments (no bill)
• You want simplified accounting

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Technical Notes

Module Integration

This module (vendor_payment_diff_amount) works seamlessly with vendor_batch_payment_merge:

1. vendor_batch_payment_merge provides the expense_account_id field
2. vendor_payment_diff_amount adds deduction functionality
3. Both modules modify _prepare_move_line_default_vals() method
4. The methods are called in sequence (inheritance chain)

Method Call Order

1. Standard Odoo: Creates basic 2-line entry (bank + payable)
2. vendor_batch_payment_merge: Replaces payable with expense (if set)
3. vendor_payment_diff_amount: Adds deduction lines and adjusts bank

Result

Final journal entry has:

• 1 debit line (payable or expense at original amount)
• N credit lines (one per deduction)
• 1 credit line (bank at final_payment_amount)

Total: 2 + N lines (where N = number of deductions)

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Validation Rules

The module ensures:

1. ✅ Counterpart line always has partner_id set
2. ✅ Counterpart line stays at original amount
3. ✅ Bank line reduced to final_payment_amount
4. ✅ Deduction lines are credits
5. ✅ Deduction lines only have partner_id if account type requires it (payable/receivable)
6. ✅ Entry is balanced (total debit = total credit)
7. ✅ All required fields are present

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Troubleshooting

Error: "Missing required account on accountable line"

Cause: An accountable line (payable/receivable account) is missing the required partner_id field.

Solution: The module now automatically handles this:

• Counterpart line (payable/expense) always has partner_id set
• Deduction lines only have partner_id if the account type requires it
• Tax accounts (liability/expense) don't need partner_id

If you still see this error:

1. Check that the partner has a payable account configured
2. Check that the expense account (if used) is valid
3. Verify the payment has a partner selected
4. Ensure deduction accounts are NOT payable/receivable accounts (use tax/expense accounts instead)

Error: "Entry is not balanced"

Cause: The debit and credit totals don't match.

Solution: This should not happen with the current implementation. If it does:

1. Check that all deduction amounts are positive
2. Verify currency conversion is working
3. Check for rounding issues

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Examples

Example 1: Simple Payment with One Deduction

# Create payment
payment = env['account.payment'].create({
    'payment_type': 'outbound',
    'partner_type': 'supplier',
    'partner_id': partner.id,
    'amount': 1000.0,
    'journal_id': bank_journal.id,
})

# Add deduction
env['payment.deduction.line'].create({
    'payment_id': payment.id,
    'amount_substract': 100.0,
    'substract_account_id': tax_account.id,
    'name': 'Withholding Tax',
})

# Post payment
payment.action_post()

# Result:
# - Payable: Debit 1000
# - Tax: Credit 100
# - Bank: Credit 900

Example 2: Payment with Expense Account and Multiple Deductions

# Create payment with expense account
payment = env['account.payment'].create({
    'payment_type': 'outbound',
    'partner_type': 'supplier',
    'partner_id': partner.id,
    'amount': 2000.0,
    'expense_account_id': expense_account.id,
    'journal_id': bank_journal.id,
})

# Add multiple deductions
env['payment.deduction.line'].create({
    'payment_id': payment.id,
    'amount_substract': 100.0,
    'substract_account_id': pph21_account.id,
    'name': 'PPh 21',
})

env['payment.deduction.line'].create({
    'payment_id': payment.id,
    'amount_substract': 50.0,
    'substract_account_id': pph29_account.id,
    'name': 'PPh 29',
})

# Post payment
payment.action_post()

# Result:
# - Expense: Debit 2000
# - PPh 21: Credit 100
# - PPh 29: Credit 50
# - Bank: Credit 1850