Ryan: Team Romney hasn't run the numbers on Romney's own budget plan

Uh, when exactly do they plan on running the numbers? After the election is over? Isn't it customary to run the numbers before you endorse a budget plan, not after it?

From PBS' Newshour:

Ryan also deflected questions about the budget proposal he authored, trying instead to shift the focus to the blueprint Romney has put forward. But when asked by Hume when the Romney plan would balance the federal budget, Ryan could not offer a specific date.

"I don't know exactly when it balances. I don't want to get wonky on you, but we haven't run the numbers on that specific plan," Ryan said.

The Romney campaign hasn't running the budget numbers on Mitt Romney's plan for the budget, but Romney is still running around saying that his plan is better? (Putting aside for a moment that the reason they haven't run the numbers if because Romney has never offered a budget plan.)

That's a bit like a family making up a budget, but not running the numbers to see if the budget even works.

How can Ryan and Romney be pushing a budget plan that they haven't even run the numbers on?  And why haven't they?