Premier Pass Help!

We have a Disneyland Signature Plus annual passes and are heading to Disney World Saturday! (Yea!!) We plan on upgrading to the Premier Pass. Naturally I have some questions. (Please help!!)
We pay the difference to upgrade - is the difference from the amount we paid before the increase or the difference between the current prices?
Does our financing it (since we’re in CA we’re allowed to pay monthly) effect anything?
Can we upgrade at Disney Springs guest services?
Can I get Tables in Wonderland at Disney Springs?

Thank you!!!

Surly someone out there has done this… :grimacing: