There's a pretty big difference between testing software with a protocol that you know and understand, and reverse-engineering the communications on a production vehicle.
Seems like the https://www.vector.com/int/en/products/products-a-z/hardware... has some similar functionality. I have never used it, but by reading the documentation I'm not sure if it would have been useful here. The frame with ID 65 which needs be overwritten, actually contains 4 different messages indicated by the last byte in the payload. To properly time the modification you need to sync up on that, which the Vector box can't do.
Also price on request, so probably not in the price range of our target audience.
Maybe drifting a bit, but I hate the business model Vector has. They have reasonably good software, but their Canoe SW has that horrible scripting language that is... well, horrible, but that everybody uses and because it's historically been used and the vendors have all the test panels and whatnot in it, the developers are locked in to pay for exceptionally expensive SW for a sub-par product.
Better than most other sw in automotive but it pales with open-source SW that does more complex things in other fields.