Report Designer Fields "Category Low" and "Category High"

Thanks. Do you know what's their purpose in the following expression?

I'm trying to understand what this means? It's the filter in the Sage standard budget report. I think it says to only include accounts from the lowest to the highest N/L account Ref, but then if it is filtering this why do you need the filter because the report should do this anyway.

Very confused. I'm trying to edit the report to show the budget for the months to date instead of for the whole year, so I started by trying to understand the filters and the variables in the standard report. I'm probably thinking about it too much, but I like to understand everything.

NOMINAL_LEDGER.ACCOUNT_REF >= CATEGORY.LOW And NOMINAL_LEDGER.ACCOUNT_REF <= CATEGORY.HIGH AND CATEGORY.CATEGORY = CAT_TITLE.CATEGORY

Thanks John.

I realised after I posted that it's because you could have a nominal ledger code outside the range for the chart of accounts, but because all my codes are in the chart of accounts I probably don't need this filter.