Have not seen anything to do with pitch for the stab Tank.
In my old airline's operations manual, there was a flow chart specific to EIU IDS-503 Software. In one of the flow chart boxes for HST operations, there was the question "Is aircraft in cruise? (Y/N)". There was a footnote relating to this which said "Cruise flight is automatically determined by aircraft pitch attitude less than 5deg for 10 minutes".