How should I derate the drive output current when operating at high altitude or elevated temperatures?

For installations above 1000 meters above sea level, derate the output current (In) by 5% per 1000 meters, and do not exceed 4000 meters. For operation above 40°C, derate In by 2.5% per degree Celsius above 40°C, and do not exceed 55°C. Additional derating is also required if the carrier frequency (P166) is increased above the default setting. (Page 11)