3 weeks is simply not enough time to reply any FDA questions/concerns. This, in and of itself, dictates a 90-day extension. However, having dealt with state and federal agencies before, it’s easy to see that they’re all crooked, care nothing about violating their own rules and regulations (like issuing a DRL just 3 weeks before a PDUFA date) and couldn’t give a rats ass about fairness, so it’s still a coin flip.