Yeah, I considered that, but order volume is almost certainly not uniform over the course of the week. Any web company could tell you that load varies quite a bit over the course of the week, and I'm sure shopping is the same.
From everything I've heard, they're an aggressively frugal company, so I would guess that they don't have the packing capacity to handle their peak days of the week, but they do have enough to handle the total week's load. Their competitors are probably overprovisioned to improve their consistency, but that leads to higher prices.
Does that match your ordering experience? Because for me Amazon have been more consistent - super saver items are consistently delivered at the end of the delivery window. Other retailers seem to have a wider distribution like you describe.
Hm, that is interesting. It's been a couple of years since I last used Super Saver shipping, so they might have changed, but I remember it being pretty variable, between slow and super slow.
From everything I've heard, they're an aggressively frugal company, so I would guess that they don't have the packing capacity to handle their peak days of the week, but they do have enough to handle the total week's load. Their competitors are probably overprovisioned to improve their consistency, but that leads to higher prices.