Installation costs will vary widely depending on factors such as how much wire he has to run, (how close is your electrical panel to where the WC will be), how easy it is to run that wire (attic, crawl space, buried, etc), and whether you have capacity and space on your existing electrical panel/service for the new circuit. For maximum charging speed you will need a 60A 240V circuit. You don't need a GFCI breaker and he doesn't have to run a neutral wire. I wouldn't be too concerned if he hasn't installed one of these before, it's pretty simple. The 'commisioning' (configuration via your cell phone) part is something you can do yourself.