I believe that H30 stops the same place as 482 and 490 at Terminal 4 (I've yet to take H30). TfL seems to call these stops 10 and 11, I'm not sure I've ever noticed the stop number when taking 482/490. For example, see:
https://tfl.gov.uk/maps?lineId=482&I...37%2C-0.446646
Also see:
https://www.heathrow.com/content/dam...travel-map.pdf