https://www.hud.gov/sites/documents/08-40mlatch.pdf
Existing Debt: Add together the amount of the existing FHA- insured first lien, closing costs, prepaid expenses, discount points, and then subtract any refund ...
https://www.fha.com/fha_article?id=1269
FHA Simple Refinance loans allows homeowners to go from a current FHA Loan into a new FHA mortgage, with no cash back to the borrower permitted.