vendor_payment_diff_amount/REQUIREMENT_EXPENSE_ACCOUNT.md

Requirement: Expense Account for Deductions

Summary

Payment deductions require the Expense Account field to be set.

This is a mandatory requirement enforced by validation.

Why This Requirement?

Technical Reason

When creating a payment with deductions, the journal entry structure is:

Expense Account (Debit)  ← Must be specified
Tax Accounts (Credit)    ← Deductions
Bank Account (Credit)    ← Net payment

Without the Expense Account, the system cannot determine which account should receive the debit entry.

Accounting Reason

The Expense Account represents:

• The full cost/expense being incurred
• The account that should be debited for the total amount
• The proper classification of the expense

Example:

• Telepon & Internet expense: Rp 2,000,000
• Less: PPh 21 withheld: Rp 100,000
• Less: PPh 29 withheld: Rp 50,000
• Net payment to vendor: Rp 1,850,000

The Expense Account (Telepon & Internet) gets the full Rp 2,000,000 debit.

Validation

The module enforces this requirement with a validation constraint:

@api.constrains('amount', 'amount_substract', 'expense_account_id', 'deduction_line_ids')
def _check_amount_substract(self):
    for payment in self:
        # ... other validations ...
        
        # Require expense account when using deductions
        if payment.deduction_line_ids and not payment.expense_account_id:
            raise ValidationError(_(
                "Expense Account is required when using payment deductions.\n\n"
                "Please set the Expense Account field before adding deductions."
            ))

When Validation Triggers

The validation error appears when:

1. You add deduction lines
2. But haven't set the Expense Account field
3. And try to save or post the payment

Error Message

Expense Account is required when using payment deductions.

Please set the Expense Account field before adding deductions.

How to Use

Correct Workflow

1. Create Payment
   ↓
2. Set Expense Account ✅ (e.g., "Telepon & Internet")
   ↓
3. Add Deductions (e.g., PPh 21, PPh 29)
   ↓
4. Post Payment ✅

Incorrect Workflow (Will Fail)

1. Create Payment
   ↓
2. Add Deductions ❌
   ↓
3. Try to Post ❌
   ↓
Error: "Expense Account is required..."

Alternative: Without Deductions

If you don't need deductions, you can use the standard payment flow:

1. Create Payment
   ↓
2. Don't set Expense Account (optional)
   ↓
3. Don't add Deductions
   ↓
4. Post Payment ✅

In this case, the system uses the standard Accounts Payable account.

Comparison

With Expense Account + Deductions

Journal Entry:

Expense Account          Debit: 2,000,000
PPh 21                   Credit: 100,000
PPh 29                   Credit: 50,000
Bank                     Credit: 1,850,000

Use Case: Direct expense recording with tax withholding

Without Expense Account (Standard)

Journal Entry:

Accounts Payable         Debit: 2,000,000
Bank                     Credit: 2,000,000

Use Case: Standard vendor payment without deductions

Benefits of This Requirement

1. Clear Accounting

Forces users to specify exactly which expense account should be used, ensuring:

• Proper expense classification
• Accurate financial reporting
• Clear audit trail

2. Prevents Errors

Prevents common mistakes like:

• Missing expense account
• Unclear journal entries
• Unbalanced entries

3. Consistent Behavior

Ensures all payments with deductions follow the same pattern:

• Always have an expense account
• Always have proper journal entries
• Always have correct tax treatment

Configuration

Required Accounts

Before using deductions, set up:

1. Expense Accounts

Chart of Accounts > Create Account
- Name: Telepon & Internet
- Code: 611505
- Type: Expenses

2. Tax Payable Accounts

Chart of Accounts > Create Account
- Name: PPh 21
- Code: 217101
- Type: Current Liabilities

Account Selection

When creating a payment with deductions:

Expense Account: Choose from expense accounts

• ✅ Telepon & Internet
• ✅ Office Supplies
• ✅ Professional Fees
• ❌ Accounts Payable (not allowed)

Deduction Accounts: Choose from tax/liability accounts

• ✅ PPh 21 (Tax Payable)
• ✅ PPh 23 (Tax Payable)
• ✅ PPh 29 (Tax Payable)
• ❌ Accounts Payable (not allowed)
• ❌ Bank accounts (not allowed)

User Training

Key Points to Teach Users

1. Always set Expense Account first when using deductions
2. Choose the right expense account for the type of expense
3. Use tax accounts for deductions, not payable accounts
4. Verify amounts before posting

Common Questions

Q: Why can't I just use Accounts Payable?

A: When using deductions, you're recording the expense directly. Accounts Payable is for tracking vendor balances, not expenses.

Q: What if I forget to set Expense Account?

A: You'll get a validation error. Just set the Expense Account field and try again.

Q: Can I change the Expense Account after adding deductions?

A: Yes, as long as the payment hasn't been posted yet.

Technical Details

Module Integration

This requirement is part of the vendor_payment_diff_amount module v2.0.0.

It works with:

• vendor_batch_payment_merge (provides expense_account_id field)
• Standard Odoo accounting (account.payment)

Field Definition

The expense_account_id field is defined in vendor_batch_payment_merge:

expense_account_id = fields.Many2one(
    'account.account',
    string='Expense Account',
    domain="[('account_type', 'not in', ('asset_receivable', 'liability_payable'))]",
    help="Account used for expense instead of the default payable/receivable account"
)

Validation Logic

The validation is in vendor_payment_diff_amount:

if payment.deduction_line_ids and not payment.expense_account_id:
    raise ValidationError("Expense Account is required...")

Summary

✅ DO: Set Expense Account before adding deductions ✅ DO: Use expense accounts for Expense Account field ✅ DO: Use tax accounts for deduction accounts ❌ DON'T: Try to add deductions without Expense Account ❌ DON'T: Use Accounts Payable for deductions

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Remember: Expense Account is REQUIRED when using deductions!

For more information, see:

• USER_GUIDE.md - Step-by-step instructions
• README.md - Module overview
• FINAL_FIX.md - Technical details