China visa and Hong Kong extension

We are on a guided tour of PRC with an optional 2 day extension in Hong Kong. We are preparing our application but not sure whether to include the days we are staying in Hong Kong on the form as 2.5 asks for duration of stay in PRC. Does that exclude Hong Kong? Do we need to make any mention on the form of our optional days in HongKong - ie under 3.7 heading?