I do believe it's a combination of your tier level and the age of your account that determines whether your stuff goes thru quickly or gets held up because it's going through CS review as well. I'm a Tier 0 (and proud of it - lol) but my account is fairly old. Once I got 25 products in the catty, like
@Devious
said above, when I submit early Monday mornings, my stuff goes though in minutes. My last submission was on a Saturday afternoon, last weekend, and it didn't come out until Monday afternoon.