I’m not an expert in IND but my understanding is

I’m not an expert in IND but my understanding is that they submit and get approved in stages. I think Rich Purcell referred to this as a rolling IND. I don’t know what if any benefit there is to doing it this way. I guess you can get approval on your submissions and make adjustments as necessary along the way rather than wait until you have the whole package done wait longer for approval or comments then correct everything at once then resubmit.

Maybe it streamlines the process a bit. Maybe in the end it’s all the same. I don’t have stats either way.