Presuming 30ft/mb, I get 960ft. At airfield A with 1020 set, sea level would be displayed as 0ft. At B if you had 1020 set then the altimeter would read 0ft at 660ft below sea level (1020-998=22 *30 = 660, high to low, down you go). the airfield is 300 ft further up giving a reading of 960ft.
What's the prize?
D
SSD obviously types faster than me and works top down, not bottom up!