If I buy a Silver Package and later want to upgrade to Gold and then further down the road to Platinum. Do I just pay the difference in package cost? I emailed sales with this question and was told yes, but the numbers in the email didn't add up 
Surely I am not the first to want to do this.
The Following was the reply to my email.
"To clarify – you only ever pay the difference.
Orthodox Silver to Gold would be $1,169.76 – we cut out what crosses over and only charge the difference. Upgrading from Orthodox Silver to Gold to platinum would be the exact same as going from Orthodox Silver to Platinum.
In short with base packages. You won’t pay for something twice and you won’t lose or save any money in how you purchase the packages. It is more expensive however to purchase bubndles on their own and then upgrade to a package that has them, because you get the credit for the price they are in the package.
Let’s say a bundle of books is $500 – that same bundle comes in a Library – your price for that library is $1000. If you purchase the bundle for $500, your price for the library goes to $950."