Yeah, it looks like there are some differences, though you might think they would standardize on something - Paypal, their own system, or whatever - for handling payments. Just for clarity, for the solar roof, with a process starting in 2019, there was first a $1k refundable deposit to get in line. Then, when I made it to the front, they asked for another $2.5k (also refundable) to complete the detailed plans (and initially, they planned to come out in person and fly a drone over the house - but turns out being in the DC area, that takes all sorts of time, so they eventually went to using satellite and other images) and then 50% each (non-refundable) at material delivery and passing inspection. The first $1k I paid when filling out whatever form was on Tesla's website for that, and the rest I paid after receiving a PayPal invoice.
While I understand Tesla not breaking up Powerwall installs into as many payments, it does seem odd they wouldn't issue those invoices in PayPal as well, but it is not surprising that they inconsistent.