Claude Fable 5 vs GPT-5.6 Luna for bookkeeping

# Marking the Claim Against the Excerpt

## Step 1 — Identify the mileage that qualifies

- Total miles driven: 18,700
- Personal miles (claimant's own figure): 6,300
- Business miles claimed: **12,400**

The excerpt says only *business* travel qualifies, so the 18,700 total and the 6,300 personal miles are irrelevant to the calculation — only the 12,400 counts.

## Step 2 — Apply the two rates

| Line | Calculation | Amount |
|---|---|---|
| First 10,000 business miles | 10,000 × £0.45 | £4,500.00 |
| Remaining business miles | 12,400 − 10,000…

The 900 miles from home to the office are ordinary commuting, not business travel, so they must be excluded.

**Arithmetic:**

- Total miles: **18,700**
- Claimed work miles: **12,400**
- Less home-to-office commuting: **900**
- Allowable business miles: **12,400 − 900 = 11,500**

Mileage allowance:

- First 10,000 business miles: **10,000 × 45p = £4,500**
- Remaining 1,500 business miles: **1,500 × 25p = £375**
- Total payable without a tax charge: **£4,500 + £375 = £4,875**

The claim’s stated personal miles would also need to be adjusted: **…