Yes that's a valid approach when you need to burn things ASAP (Titan egis). Ideally, though, you would be using flares during that phase to hit both Titan and his two egis. I'd only multidot in various parts of T4 and at the beginning of T5 (which you can AoE down anyways).

Your single target rotation is fine. What does your AoE rotation look like?

I know a lot of BLMs tell me they are doing what I am advising but rarely see this. Do you have any streams available so we can watch you play BLM?