Source: https://guthlabs.ai/docs/instruments/mortgage-vs-rent-comparator/qualification/

instrument qualification / verified-with-binding-errata

# Mortgage vs Rent Comparator qualification

Verified with errata that must be applied at binding time.

Status: **VERIFIED_WITH_ERRATA**Lifecycle: **verified-with-binding-errata**

## Ledger verdict

Verified with errata that must be applied at binding time.

**Status**: VERIFIED_WITH_ERRATA

**Tranche**: tranche-6

**Review vectors**: 4

**Ledger rows**: 1

## Applied errata

````
[
  {
    "vector": "1-4",
    "field": "total_rent_cost / buy_minus_rent / break_even",
    "wrong": "rent cost includes the renter KEEPING their down payment (e.g. v1: 25545.65 rent + 63000 grown savings = 88545.65)",
    "correct": "total_rent_cost = rent outlays only (v1: 25545.65 under her stated monthly-growth convention); the down payment is the renter's asset, not a cost — at most the foregone RETURN belongs on the buy side",
    "cause": "economically inverted model that makes buying look better by ~the whole down payment; ALSO internally inconsistent: v1/v2/v4 add the grown balance, v3 adds the raw 50000 with no growth"
  }
]
````

## Adversarial re-test context

The full catalog was re-tested from boundary, convention, and self-check angles in 2,787 requests. Five genuine computational defects were independently verified and corrected. This page reports the current ledger state for this instrument; it does not imply product deployment or interface qualification.

## Release gate

Bind every attached correction, replay the affected vectors, enforce boundary validation, and preserve evidence before describing the executable surface as qualified.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/mortgage-vs-rent-comparator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/mortgage-vs-rent-comparator/mechanism/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/mortgage-vs-rent-comparator/implementation/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `STRESS_TEST_RECEIPT.json`

- `tranche errata record`