Dela Cruz Glass billed the tempered glass panels at ₱3,450.00 a piece , but their quote has them at ₱3,150.00 . For 12 pieces that is ₱3,600.00 over, so the invoice should total ₱66,000.00, not ₱69,600.00.
I drafted a reply asking for a corrected invoice. Change anything before you send it.