There is no such thing as "DFA Waivers." Nor is there anything called "trade waivers." DFA and waiver rules are the same year-round. Trading rules change after August, but the waiver process is identical. The reason to do a DFA instead of just putting someone on waivers is that when you DFA someone, they immediately come off your roster. When you waive someone, they don't. Most players get waived in August but keep right on playing for the same team and never get traded or cut. When the DFA happens, the team gets 10 days to decide what to do (cut, trade, waive/reassign to minors, or put back onto the roster).