I'm assuming your 1:9 is from "European Concentrate", where that would be "dilution B" (1:9 from syrup would be stronger than dilution A, which would give extremely short times, like a minute or 2).

The Massive Dev Chart does indeed give times for HC-110 dil. B - you have to select "Ilford Pan films" from the drop down.

Incidentally, is this Pan 400 you're using new stock? If so, where did you find it?