multidevice license

Secureline - I currently have 2 licenses for iOS and 1 license for the desktop mac. I like to know how to convert these over to a 5 device multi device license. What happens to existing license when I buy the multi? Will expiration dates be extended or I end up with separate expirations. Will they need to uninstalled and canceled then proceed with the new license?
I have (2 iOS tablets 1 iOS phone 1 android phone and two desktops) Trying to find the best way to cover these with as few license / renewals to keep track.

Thanks
Steve (tripod2go)

An question which would help is verifying that the Multiple Device crosses platforms? i.e. Android, iOS Macos(OS X) PC

You can renew your license, only. Of course, only when it’s next to the expiry date.
When you buy a new one, it will be a separated licenses and when the old one expires, you have to change it to the new one.