I have a hard one for you.

if Sheet1 A1 is = Sheet2 A1 and if Sheet1 OFFSET from S1 down 2 left 1 is
equal to Sheet2 OFFSET from A1 down 2 left 1 return nothing otherwise IF
different return what is now in that cell of Sheet2. Then continue down until
the customers orders are all compared.

300+ Multiple customer with multiple order.

Clear as mud, right

Sheet 1 Sheet 2
A B A B
1 ABC Comp ABC Comp
2
3 Pickels 49 Pickels 9
4 Peaches 10 Peaches 15

TIA
--
Pete