Do Not Pay Any Less, Mrs Mess Puzzle

Mrs Mess was buying a set of garden furniture. The bill was seventy dollars.

She gave the attendant what she thought were two $50 notes, (actually two $100 notes).

The attendant was sleepy and didn't notice either, so he gave Mrs Mess what he thought were three $10 notes (actually three $50 notes).

Who ended up better off than they should?