It is difficult to even speculate on outcome of IPO. It looks like from S-1 that distribution from IPO will be generated from the two new pipelines and some growth in NGL storage and some from increased cavern storage.
Comparative example in recent times in PAA-PNG IPO
What will happen to NRGY distribution after IPO. An "optomistic" speculation would be it is held flat but that may be only a 50/50 probability based on price recent action. If held flat could be flat for some time to come. Again all just speculation but management appears to be trying to stay ahead of the curve and position NRGY for something else.