Behavior before:
The import flow could crash with an "Expected singleton" error if multiple
journals shared an IBAN. Additionally, the system blindly accepted the
current context ('self') as the target journal, even if its currency or
bank account mismatched the statement, often leading to avoidable
UserErrors.

Behavior after:
The system now validates 'self' against the statement's currency and IBAN
before assignment. If a mismatch is found, it automatically searches for
the correct journal. The search is now restricted by currency and includes
a limit=1 to prevent crashes and ensure accurate selection.

Root Cause:
In _find_additional_data(), 'journal = self' was assigned without validation.
Furthermore, the fallback search lacked a record limit and currency matching
logic, allowing multiple records to be returned when duplicates or
multi-currency setups existed.

Fix:
- Added validation for the initial 'self' candidate (currency and IBAN match).
- Refined the search domain to include currency matching (journal or
  company fallback).
- Added limit=1 to the search to guarantee a singleton recordset.

opw-5462037

**Steps to reproduce:**
* Install the *Accounting* module.
* Install localisation modules for two different regions:
  * *Belgium* (**l10n_be**)
  * *Luxembourg* (**l10n_lu**)
* Configure two companies, each assigned to one of the above regions.
* Create fiscal positions:
  * In the Belgium company, create a fiscal position for Luxembourg.
  * In the Luxembourg company, create a fiscal position for Belgium.
* Go to *Accounting > Configuration > Settings*. Enable *Inter-Company Transactions*. Enable synchronization of *Vendor Bills and Invoices* for both companies.
* Create an invoice in the Luxembourg company. Select a partner belonging to the Belgium company. Add a product with applicable taxes.

**Observed behavior:**
* A validation error is raised: 'This entry contains taxes that are not compatible with your fiscal position. Please check the country set in the fiscal position and in your tax configuration.'

**Cause:**
* During intercompany bill creation, a foreign fiscal position is applied before recomputing taxes.
* If no mapped foreign taxes exist, the system keeps domestic purchase taxes.
* This leads to a mismatch between taxes and fiscal position, triggering the validation error.

**Fix:**
* Add a safeguard in *_inter_company_create_invoices()*.
* After *_inter_company_sync_invoice_line_taxes()* recomputes taxes, *_inter_company_has_incompatible_fiscal_position_taxes()* checks whether the fiscal position is incompatible.
* If incompatible, the fiscal position is removed and taxes are recomputed without it.

opw-6103671

…d tax subtotal

**STEP TO REPRODUCE**
1. Create an invoice with an early payment discount (payment terms) with an invoice line with a 0% tax.
2. Generate the ubl for the invoice by sending it to peppol.
3. Validate the generated ubl, you'll get the following errors: [BR-E-08]-In a VAT breakdown (BG-23) where the VAT category code (BT-118) is "Exempt from VAT" the VAT category taxable amount (BT-116) shall equal the sum of Invoice line net amounts (BT-131) minus the sum of Document level allowance amounts (BT-92) plus the sum of Document level charge amounts (BT-99) where the VAT category codes (BT-151, BT-95, BT-102) are "Exempt from VAT". [BR-S-01]-An Invoice that contains an Invoice line (BG-25), a Document level allowance (BG-20) or a Document level charge (BG-21) where the VAT category code (BT-151, BT-95 or BT-102) is "Standard rated" shall contain in the VAT breakdown (BG-23) at least one VAT category code (BT-118) equal with "Standard rated". [BR-S-06]-In a Document level allowance (BG-20) where the Document level allowance VAT category code (BT-95) is "Standard rated" the Document level allowance VAT rate (BT-96) shall be greater than zero.

**CAUSE**
- When there is a epd, we append a new tax subtotal. Which means we end up with multiples tax subtotal for the tax category E. We do the same for emptying taxes. The fix add a step that merges all the tax subtotal of the same tax category into one.
- When there is a epd, the allowance is generated with with a tax cargory S even with the tax percentage is 0. It should be E for 0% tax.

opw-6075910