Many screens have the Remove Limit link at the top. If you had 1000 products and the limit was not initially imposed, the product list would take much longer to load.
This can be seen in the Accounts section under Transactions, especially when you’ve been running for a year or so and there are 10000+ or 100000+ Transactions to list. Initially the screen loads the list quickly, because it is limited, but when you Remove Limit, you’ll notice a delay while the rest of the Transactions load.
I don’t know if there is a way to sort Product Categories (a products Group Code), but you might try changing your single-digit groups to include a leading ZERO (ie. 04, 05 instead of 4, 5)… that might do the trick.