# C1455 — Explain the LXX–MT cumulative order change

## Question

How does a20-year upper-leg source difference become a2000-year reversed difference?

## Sources

```json
[
  "LXX and MT cumulative source legs"
]
```

## Opened utc

2026-09-29T01:17:04.328987+00:00

## Results

```json
{
  "source_lower_gap": 910,
  "source_upper_gap": -20,
  "inverse_lower_gap": 910,
  "inverse_upper_gap": -2000,
  "source_head_gap": 890,
  "inverse_head_gap": -1090
}
```

## Finding

The retained lower gap910 combines with upper−20 before reversal and upper−2000 after it: source890 becomes inverse−1090. The changed decimal place explains the reordered heads.

## Reassessment

Use the MT/SP preserved610 gap to explain the third cumulative comparison without treating it as independent.

## Checks

```json
{
  "correct_gaps": true
}
```

## Closed utc

2026-09-29T01:17:04.329348+00:00

## Record provenance

Exact record hash: `ade027f64326d69ba9af9eeca2f4ba6fe327dae84c6380a43d8af9a6b5227c68`

Source journal: `Research_Cycles/C1433_C1482/journal.json`