Event Edition is purchased through the App Store and is associated with your Apple ID. Apple will allow you to use it on multiple devices at a time, typically with a limit of 5-10 devices, if they are all logged in with the same Apple ID.
Learn more about managing associated devices on Apple's website.
HALO app licenses are associated with your Simple Booth account and only allow you to use the app on one device at a time. To use more devices at the same time, you will need to purchase more licenses. You will need to have as many licenses as devices that you expect to be in use simultaneously.
We offer discounts on volume license purchases.