[turp mcspray]

In the original post he said he was spraying DCC which is single stage. (correct me if this is wrong) Base coat is DBC. If you are spraying base coat with no hardner, you could let it set iindeffinitely and still clear over it. The longer it sets, the more chance you have for contamination of sorts. If they said there is no window, and some guy sprays the base and then 2 months later sprays the clear, and then has a problem he will blame the paint. The manufacturer must cover their a$$ from these guys. So they put a window on it. On a product like base coat or laquer you could let it set forever , and when you spray more base on or clear, as long as the surface hasn't been compromised, it WILL stick.
If you have a problem in your base, as soon as the paper won't stick, you can sand it and spray more base on that spot, then clear as you normally would.