I see, that's disappointing, but again thanks for the quick replies.
Beyond the sorting of my old collections, I think this is quite problematic for even ingesting any NEW videos I take with my A6000. It seems that unless I ingest off the SD card the day I record a video, it's going to be stored in the wrong day's folder, apart from the photos it was taken with.
To keep a properly sorted file structure I guess I'll have to import through Lightroom. And then switch to PM for tagging/culling through the folders LR created (but what if there's dozens of days/folders worth of photos/videos from an import?)... and then switch back to Lightroom to remove the tagged culls and continue development on my picks. Hmm. Not a streamlined workflow at all. Open to suggestions.
edit: I've been testing a bit more with the AVCHD files - set my camera back 2 months, recorded a video, ingested it from the card, and PM actually put it in the correctly dated folder from two months ago. Huh.