Ryan hasn’t “crunched the numbers”; he has just scribbled some stuff down, without checking at all to see if it makes sense. He asserts that he can cut taxes without net loss of revenue by closing unspecified loopholes; he asserts that he can cut discretionary spending to levels not seen since Calvin Coolidge, without saying how; he asserts that he can convert Medicare to a voucher system, with much lower spending than now projected, without even a hint of how this is supposed to work. This is just a fantasy, not a serious policy proposal.
The Ryan plan is snake oil. I’m starting to think that Romney picked him to divert from his tax disclosure problems.