Once the school has determined the types and original amounts of the underlying loans, it must prorate the outstanding principal balance amount on the Washington consolidation loan in the same ratio that each of the "PC" original loan amounts is to the original Washington consolidation loan amount. For example, assume that a borrower's original principal balance was composed of 25% subsidized loans and 75% unsubsidized loans. The school can assume that 25% of any remaining unpaid balance is subsidized and would be counted towards the borrower's subsidized aggregate loan limit and 75% towards the borrower's unsubsidized aggregate loan limit.