Crub, wiggle, nosh.
(The above has been brought to you by the internal workings of my brain as it attempts to handle the latest bit of input.)
ME: "Well, it looks like a total rewrite of the code."
MGR: "You don't have to rewrite everything, do you?"
ME: "Only the stuff that's changing."
MGR: "How much is changing?"
Okay, I know this is going to sound weird, but I'm researching breast shape. And while the internet is full of booby pictures, studying them academically takes all the fun out of it.