I'm afraid this is an issue I've had with vbulletin for a while - either new posts updates too quickly (as you point out) or else to counter this they update too slowly (ie, each day) which causes additional confusion.
My personal tip - click on new posts, then open each discussion in a new window as required. That way, you keep with your original list, and can refresh that after you've checked out any posts of interest.
Hope that helps.
