GPT-5.3-Codex vs GPT-5.6 Sol for spreadsheets & Excel

You have **one definite formula fault** and one likely logic issue:

1. **`VLOOKUP` column index is invalid**  
   - `Sheet2!A:D` has only **4 columns**, but you asked for column **5**.  
   - This must be `4` (or expand the lookup range).

2. *(Logic, not syntax)* Your `SUMIF` criteria `">"&TODAY()-30` includes **everything after 30 days ago**, including future dates.  
   - If you truly mean “last 30 days”, use `SUMIFS` with an upper bound too.

### Minimal corrected version (fixes the hard error):
```excel
=SUMIF(A:A,">"&TODAY()-30,B:B)+VLOO…

**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)
```