Just posting in case this may help someone else. My son had a procedure last year month and with my high deductible insurance, I owed $3700. While I could have probably paid in full I wanted to work out a payment plan since I know hospitals will work with you interest-free for a year (Edit: people have commented that they will work interest-free for much longer) and it never hurts to have money in the bank in case of emergency.
I called and spoke to a CS rep for the hospital and simply asked to work out a payment plan. She said I could pay a monthly amount for a year OR pay in full right now and get a 20% discount! I was ready to leap out of my chair but thankfully composed myself and said, while I appreciate that offer is it possible you could do more. She said that is the most she could offer without manager approval. I asked if she would ask her manager. After a minute hold she came back with 30%!!!
I paid in full and saved $1200. Never hurts to call and ask