Aperture from Mac App Store and Multiple Comps, answers not clear

I've ton tons of searches, but can't get a firm answer. I know you CAN install Aperture on multiple macs, but with the version from the Mac App Store, can you use both at the same time.

Issue I have is that I will have 3 macs, I bought the $200 Aperture before the Mac App Store was around for my main Mac, then for my other laptop I bought the Mac App Store version. I now ordered a MacBook Air and need another copy. I do anticipate using this at the same time on many occasions as me and my wife use this a lot for light editing. I don't mind paying for another copy but if I go to purchase it it will already say it's purchased and download the same license....I'm assuming anyway....any insight?

Thanks in advance...