Mersal One Invoice, Two Tax Treatments
The single statement is not homogeneous
A legal bill is rarely one kind of thing. Consider a routine matter closing. You charge for professional time, which most VAT regimes treat as a taxable service. On the same statement you recover a court filing fee you advanced on the client's behalf, a genuine disbursement that many regimes treat as outside the scope of tax, or exempt. You also pass through a translator's charge that carries its own treatment.
Three lines, three tax positions, one document the client expects to receive as a whole. This is the ordinary shape of legal billing, not an edge case. The question is whether your billing system can describe it honestly.
Why a global rate forces an error
Software that applies one tax rate to an entire invoice cannot represent this statement. It offers two escapes, and both are defective.
The first is to force a single rate across every line. Tax the disbursement that should not be taxed, or exempt the service that should not be exempt. Either way the declaration filed against that invoice is wrong, and the error is baked into a serial document you cannot quietly alter later.
The second is to split the work into separate invoices, one per treatment. Now the client receives fragments for a single engagement, your serial sequences carry artificial gaps, and reconciliation costs multiply. You have traded a clean statement for paperwork that obscures the matter.
Ruling tax at the line
The correct unit of taxation is the line, not the invoice. Each line carries its own rate: standard, zero, or exempt. The invoice then sums honestly, showing taxable and non-taxable subtotals side by side, and the declaration derived from it is simply true.
Mersal rules VAT per line, so one statement can mix a taxable service with an exempt disbursement and still issue from a single sequential serial in the correct book. The document matches the work. Nothing is split to satisfy the software.
The audit consequence
Getting this wrong is not a rounding matter. An invoice freezes at issue, and its tax figures become the basis for a period return. A wrong rate on a wrong line produces a wrong return, and the discrepancy surfaces on examination against the original document that no one can retroactively fix without an auditable reissue.
An auditor reading a per-line statement sees the reasoning on the face of the bill: this line taxed, this line recovered, this line exempt. Clarity at issue is what survives the review years later.
Per-line ruling is not a convenience feature. It is the difference between a bill that tells the truth about the work and one that has been bent to fit a tool. When a service, a disbursement and an exempt pass-through meet on the same page, the honest invoice treats each on its own terms and still issues as one clean, sequential document. Everything else is either a false declaration or unnecessary paper. Tax the line, not the letterhead.
Matters, conflicts, VAT billing, sealed receipts and the docket, in one defensible system.