It's not so much about adding them out of order, more about how DMM sped up the blooming schedule. They started with 4 blooms every second week, then began adding artless blooms during the first week of events(including Lycoris & Night Phlox). Eventually, they were adding 8 artless blooms during the first weeks and 4 with, 4 without art during the second weeks until everyone had bloom abilities.

They're still adding bloom artwork at a rate of 4 characters per event, so they're not clearing that backlog in the foreseeable future.