BLM Merits, AM II

I have some questions about AM II, BLM merits. I have been looking around and I have seen it done so many ways I'm not sure what way to go. Right now I feel it would be best to max out Burst II and Freeze II. I already have Ice Potency and Lighting Potency maxed, so it would go even better with that. I don't really see a time where I would be using Flare II or Flood II over Freeze II or Burst II. If I'm wrong, please correct me. Thank you for your time.