Data model
The pricing waterfall
A data model of the steps that resolve a final price, showing how base rates, tariffs and adjustments combine in a set order.
The final price of a charge resolves through an ordered set of steps. Each step takes the running amount, applies one rule, and hands the result to the next, so a base rate becomes a settled price the same way every time. This page sets out that waterfall: base rates, tariffs and adjustments combining in a set order.
The ordered steps
The waterfall runs nine adjustment steps in a fixed sequence. The table lists them in order. The first can raise the amount; the rest hold or lower it.
| Order | Step | What it does |
|---|---|---|
| One | Tariff tier | Replaces the base rate with the payer's contracted tier price. |
| Two | Package inclusion | Sets the line to zero where the item sits inside an active package. |
| Three | Scheme concession | Applies a government scheme's own price. |
| Four | Discount | Applies an approved discount, held to the site's cap. |
| Five | Sub-limit cap | Holds the line to a payer's per-category cap, and to a statutory price ceiling. |
| Six | Room rent proportion | Apportions room rent by the payer's rule. |
| Seven | Coverage cap | Caps the payer's cumulative liability at the sum insured or approved amount, passing the excess to the patient. |
| Eight | Co-pay | Deducts the patient's agreed co-pay share. |
| Nine | Rounding | Rounds the line to the nearest rupee. |
The adjustment trail
Every step records what it did. Each writes one entry showing the amount before and after, so the move from the gross rate to the net price reads as a sequence of stated adjustments. A correction adds a new entry that supersedes the earlier one, and the earlier entry stays in place, so the trail only ever grows.
The trail is append-only
An adjustment is added rather than rewritten. A re-price supersedes an earlier step with a new entry, so the full derivation of any price stays reconstructable.
Tax and the split
After the adjustments settle the amount, tax is calculated on the adjusted price and recorded as its own line. Vault then computes the split once: how much the payer covers and how much the patient owes. Invoices, account statements and insurance claims read that single split rather than working it out again.
The adjusted amount that tax is charged on.
The tax for the line, recorded with its rate and code.
The share the payer carries.
The share the patient owes.
Effective dating
Each step resolves against the charge's service date. A rate, a policy or a tax schedule that changes later leaves an already-priced charge as it stood. The price a charge carries is the price that was in force when it was raised.
Read how payers set the tariffs and caps that drive these steps.