This must have been a NG with short field package (the regular NG only have blow back for flaps 30 and 40).
These aircraft are slippery since you only get full leading edge slats when flaps > 25.
The regular NG get full leading edge slats when flaps = 10 or greater.
This makes a big difference when you are hot and high.
Not sure if they have a mixed fleet or only short field versions, but if you are used to the
basic type, you can get a surprise when you fly the short field type.
This may or may not have been a factor, just throwing it out there.