Most large commercial utility-level deployments have negotiated terms for maintenance and warranty. Smaller to that of large aircraft purchases. They have posted prices, but as the scale rises so too does the negotiated terms.
I have not been involved in one of those for a long time. When I was there were some very large ones. The variations have always surprised me. Hint: with both electric utilities and airlines, brand loyalty can be done, but the vendor will pay dearly for that. One fo the largest variable is in delivery times and penalties for late delivery. Tesla has been exceedingly competent in that respect by indications from South Australia, part fo which were does semi-publicly.