Hi gmat4122,
This sounds like a Customer Service issue for the team at
www.mba.com. Since the two scheduling options (At-home vs. at a Testing Facility) are separate options, IF the Test Center remains open and you choose to 'cancel' your appointment, then you will likely be charged a fee (based on your location and how early you cancel) since YOU'RE the one making the decision. If the Center ends up being closed due to the Covid-19 virus, then you would not be charged. It's possible that you might be able to reschedule an on-site Exam to an At-home appointment, but that would likely involve Tech Support on their end, so if that's something that you want to try, then you have to contact them about it.
GMAT assassins aren't born, they're made,
Rich