I agree with AngelsPeak, but, I'll even take it a step further. I think it's safe to say that it's not just an interpretation difference between guys and girls. I think it's also an individual interpretation that gets into the mix. There are some girls that will give certain "signals" while the same signals from another girl won't be taken the same way. I think everybody has their own way of "flirting" and unfortunately no book will spell out a 100% proven system.

There is no way around the old fashioned tried and true method of simply asking for the date. You can get mixed up with signals and reading the other person forever. I say just go for it. Worst case scenario you will get burned and/or roasted without mercy. It's just easier going in with that mentality.