Sweeney Todd show count question

This has probably been addressed already and I just missed it... but any idea why they're only doing 7 shows a week?

A February article in the NY Post says:

"Once ‘Sweeney Todd’ leaves Fleet Street and lands on 46th Street in Midtown Manhattan, the show will adopt a fairly typical schedule.

Audiences can catch “Sweeney Todd” five nights a week from Tuesday through Saturday at 8 p.m. Sunday matinees begin at 3 p.m.

Once the musical officially opens on March 26, Kail’s production will settle into a standard eight-show week routine with Wednesday and Saturday matinees peppered into the schedule."

But they're only booking 7 shows a week through January it looks like (except holiday weeks when they go to 8). Just curious about this. I don't know much about Broadway inner workings, but I thought 8 shows a week minimum was one thing I could count on.

Josh Groban only wanted to do seven shows a week. After the Tonys I bet he doesn't do Wednesday matinees either.

They probably used the shows when Groban called out sick as aa test to see how many people ask for refunds. The house was pretty full the night I saw it with Christopher, but I definitely saw people in line for refunds.