How to speed up a query with a lot of subqueries

I have a query which uses a series of functions to return the status of each document for a loan. SELECT loan_number, borrower_name, get_application_status(loan_number, date_application_ordered, date_application_verified), get_appraisal_status(loan_number, date_appraisal_ordered, date_appraisal_verified), get_endorsement_status(loan_number, date_endorsement_ordered, date_endorsement_verified), get_waiver_status(loan_number, date_waiver_ordered, date_waiver_verified), get_insurance_status(loan_number, date_insurance_ordered, date_insurance_verified) FROM loans_table WHERE loan_type IN ('A', 'B', 'C') AND filing_date > TO_DATE('30-OCT-12') AND filing_date = date_verified THEN RETURN 'Not Verified Since Last Upload'; ELSE IF last_upload_date < date_verified THEN RETURN 'Verified'; END IF; END get_waiver_status; How do I get the query to return faster? I have made indexes on loan_number and filing_date. I tried creating a trigger on documents_table to store the last upload_date of a document into a new table for the function to retrieve, but if a document is deleted, I need to be able to select the next latest upload_date from documents_table, which I can't do from within the trigger because I get a mutating table error. I am using PL/SQL on Oracle 10g R2.