There is nothing eBay can do about people who don't pay attention to what they're doing, and/or decide to rate on time it took to receive as opposed to time it took for the seller to post.
It doesn't matter that the DSR on FB profiles says "Postage time", this is what it says when someone goes to leave feedback:
It is very clear to me, and the average eBay I suspect, what the rating is asking for, but many people have no idea when an item was actually posted because receiving an item is the first "real" indication from the seller that their purchase was acknowledged / handled, they don't take any stated handling time into account, and just have the notion that a domestic purchase should arrive in a couple of days, and if it doesn't, it's gotta be because the seller delayed postage.
I know that eBay send auto-generated emails at certain points in a transaction, but most buyers know they're auto-gens, and many also know marking an item as posted doesn't make it so (instances where tracking numbers can prove date and time of lodgement notwithstanding).
I know my practices aren't for everybody, for reasons of practicality or otherwise, but I send a message to most of my buyers as soon as possible after payment that advises of exact postage date, which means that they get real confirmation within a very short time (rather than up to several days later) that their order has been acknowledged and is genuinely progressing. If payment is via eCheque, I make it very clear the item will be posted when PayPal clear the funds and provide the estimated clearance date. I've been doing it that way for 4 years, and postage time is the one DSR I have never had a low rating for. (I'll get one now, most likely 
)
Incidentally, you can't block eCheques on eBay, but you can if you accept it on your own website, and maybe some other ecommerce sites.
