Flight stops at another city in China

New Zealand passport. Flying from New Zealand to Italy via Guangzhou. I would like to have 2 nights in Guangzhou and use the 72 hour visa. But on some days of the week the airline stops in Wuhan for a short while on the way to Rome. I presume if I travel on these days I won't be able to use the 72 hour free transit as the plane is not flying directly out of PRC. Please confirm thanks.