The Typhoon H and the 920 do not share the same motors. Not even close to the same. The uses an 800kV or so motor, the 920 uses a 340kV motor. The upper limit of a 920 is 1000m above the launch point.
The greatest factor with high altitude flight is reduced flight time. Battery drain is faster at high density altitudes.
Edit;
After being called out on my use of “high density altitude” I ‘spose I need to define that better for those unfamiliar with pilot speak. Propeller, airfoils and normally aspirated engines all decrease in performance at high altitudes, along with altitude elevated due to low oxygen (O2) density, with the lower density induced by temperature and humidity. As altitude increases, O2 density decreases, and temperature and humidity levels above “standard” further reduce O2 density. The base line “standard” is, when at sea level, being at 29.92Hg, 59*F, with zero humidity, with increases in altitude decreasing in pressure and temperature at a standard pressure/temperature lapse rate.