# Supplemental LXX comparison — corrected 8464 crossover

24 September 2026. Dean's supplemental observation, verified for awareness. **It does not redirect the current Mirror/529 research.**

The operative source frame uses the existing full-430 comparison, Terah +60 OFF, LXX native Cainan ON and MT Cainan OFF. It opens no new upstream Gear states.

| Event | MT source BC | LXX source BC | LXX earlier by |
|---|---:|---:|---:|
| Creation endpoint | 4114 | 5494 | 1380 |
| Jared birth | 3654 | 4534 | 880 |

File_18's minimum-frame rows give MT3899/3439 and LXX5279/4319. Adding the existing 215-year frame adjustment gives the table above. Thus Creation→Jared is 460 in MT and 960 in LXX. The offset changes by 500; 1380 must not be applied uniformly to Jared.

File_18 §4's introductory +1380 shorthand cannot override its row-specific data. This clarification is captured here without changing the canonical file.

The existing crossover rule is P_b+8464=Q_(8464−b), with P_b=(b+1)t/bn BC and Q_c=AD ct/(c+1)n.

| Event | Source pair | Landing after +8464 | Reflected comparison anchor | Same-season gap | E=25/23 expansion |
|---|---|---|---|---:|---:|
| LXX Creation | 5495t/5494n BC | AD2970t/2971n | Conquest AD1406t/1407n | 1564=68×23 | 1700 |
| LXX Jared | 4535t/4534n BC | AD3930t/3931n | Exodus AD1446t/1447n | 2484=108×23 | 2700 |

Both physical seasonal crossover checks use the no-year-zero subtraction:

5495+2970−1 = 5494+2971−1 = 8464.

4535+3930−1 = 4534+3931−1 = 8464.

The subsequent comparisons are between reflected AD anchors and AD landings, in matching seasons. Their difference is

\[
2484-1564=(3930-2970)-(1446-1406)=960-40=920,
\]
\[
920\times25/23=1000=2700-1700.
\]

These expand the comparison gaps. They do not replace the 8464 crossover by an expanded bridge, and they do not identify new historical events at the generated landings.

**Correction:** AD3930 and the 2484-year comparison replace Dean's earlier AD3746/2300-year claim in this observation. The earlier claim is inactive.

Source references: File_18 §§2.1.3 and 4.1 plus its full-430 adjustment; the supplied axis report §§1.2–1.3 and 8.2; Dean's current instruction. Exact excerpts are S01–S05 in the C275 passage ledger. Machine readout: SUPPLEMENTAL_LXX_RESULTS.json.

The A/B/C placement audit and its next step remain unchanged by this supplement.