Adding one more data point here. Had more issues with my suspension recently with loud squeaking sound from the front (different from last time but still squeaking-like sound). This time I had relocated to California and took it to the Tesla service in Hawthorne. Compared to the service center in NY, this was a night and day difference in customer service but that's beside the point.
Tesla diagnosed it with castor/camber arms issue. They ended up replacing all 4 arms and doing a full alignment. Total cost ~$2100.
Contacted X-Care via email about payment, they asked for service advisor's email, I contacted service advisor and forwarded the email address to XCare. They made the payment within an hour (it was probably less than 30 mins but I didn't see when the total due on my Tesla app dropped to $100 until about an hour later), and I made the remaining $100 payment on the app.
The car is now good as new. Again, overall positive experience so far with XCare and considering the expenses I've had, I'm glad I got the coverage.
Only open question - My appointment also had a line item for an issue with sunroof brackets I had. At the time of service, Tesla didn't have parts to replace and they ended up making a follow up appointment for me in January when they expect to have the parts in stock.
I'm not sure if I'll need to pay the $100 deductible again for the next visit or if it would be covered under the same claim/visit I have open since it should've been taken care off in one visit if they had the parts in stock.
I'll report back after the follow up appointment.