MD-80 penalties for ....
According All Operator Letter AOL C1-E60-HHK-89-L038 issued by Douglas on January 19,1989:
# When OAT is at or below 6ºC and fluids have been applied, the use of derated thrust is recomended only when the assumed temperature and associated takeoff speeds are determined based on an Equivalent Weight which is 5% above the ATOW.
# When OAT is above 6ºC , standard derated thrust procedures can be be used if desired.
REGARDS.