They are all probably dummy dates - meaning, they want to have some tickets on sale to at least be earning a little revenue during this time, but only selling 4 shows a week is a good contingency plan in case they have to reschedule those dates, or cancel them all together (less tickets = less headache). So, even if they did return at 4 performances a week, they're all set and already on sale. But if they have to cancel them further, they'll only have half as many performances to worry about refunding.