Hi Rambomonkey75 and welcome to the forum.
Rambomonkey75 wrote:if I was to purchase Amplitube 4 would I be able to use this software on both my Windows 10 PC and my Macbook Pro without having to purchase the software twice for each OS?
Yes, absolutely. You'll find two separate download links in your User Area for the software, so you just need to make sure you get the correct one depending on the machine.
I should draw your attention to the EULA which states that you can install "...on up to three (3) computers, provided that (a) each computer is owned by (or leased to) and under the exclusive control of the Licensee; (b) the Product shall NOT be used simultaneously on more than one machine, and (c) any computer(s) with the Product installed shall not be sold, rented, leased, loaned or otherwise be removed from the Licensee’s possession without first removing (uninstalling) the Product..."
Obviously, the installations will each take one authorisation, but you start with ten in your User Area so plenty to be getting on with.
Hope that helps.