Would you consider updating Add-on Manager to enable multiple scenery/tool item purchase to be done all at one time?
It's already possible, if you select the "Buy on Web / PayPal" button, that will launch the browser to buy on a web site that has a cart-like interface, were you can first put all the product in a Cart, then purchase all of them in a single transaction, and your email receipt would show multiple product, each one with its own Serial Number, that can be activated with the "Register Serial" option.
The "Buy on Web / PayPal" accepts BOTH PayPal AND Credit Card payments.
Doing like that inside the integrated purchase procedure, it's just not possible and it's out of control of the Addon Manager because, from the moment you press the "Buy" button to the end of the transaction, it's all entirely under control of Esellerate, and their integrated purchase method doesn't have a cart-like interface, but is tailored for a single product transaction only.
Looking forward to KFLL and "AES-like" ParkMe.
There will be no new ParkMe features at KFLL for the release date. We are doing something that will be so good, that it's worth waiting, and it's not worth delaying KFLL because of that.