GPT-5.6 Sol vs GPT-5.6 Terrafor spreadsheets & Excel

**Fault:** `VLOOKUP` requests column **5**, but `Sheet2!A:D` contains only **4 columns**. This normally produces `#REF!`, not `#VALUE!`.

Assuming the intended return column is **D**, use:

```excel
=SUMIF(A:A,">"&(TODAY()-30),B:B)+VLOOKUP(C1,Sheet2!A:D,4,FALSE)
```

The original `SUMIF` criterion is valid; the added parentheses simply make the date calculation explicit. If a fifth return column is actually required, the lookup range must extend to column E instead:

```excel
=SUMIF(A:A,">"&(TODAY()-30),B:B)+VLOOKUP(C1,Sheet2!A:E,5,FALSE)
```

Faults:

1. `VLOOKUP(C1,Sheet2!A:D,5,FALSE)` requests column **5**, but `Sheet2!A:D` contains only **4 columns**.  
   - If the intended return column is `D`, use column index `4`.
   - If a fifth return column is actually needed, the lookup range must extend through column `E`.

2. The date criterion is clearer and safer written with parentheses around the date calculation: `">"&(TODAY()-30)`.

Corrected formula, returning the value from column `D` of Sheet2:

```excel
=SUMIF(A:A,">"&(TODAY()-30),B:B)+VLOOKUP(C1,Sheet2!A:D,4,FALSE)
```

If you…