I see the argument, although it's not just a matter of "letting shareholders know", it's that they'll be letting EVERYONE know. What I mean by that is it would be in the company's best interest to choose a strategic time for releasing such news (i.e., FDA approval). They'll likely want to attract potential investors to the IPO rather than those who are already committed from the awarded dividend shares.
I'm comfortable waiting for now since the FDA approval for HemaXellerate I looks to be close, and IMO the Regen IPO will come along with that.