The 'Advanced' refers to the Airframe NOT the engines.
This, from memory of 25 years or so ago, meant the ADV had more flap settings and I think revised leading edge devices.
Some Operators had later, more powerful engines, fitted -15's -17's etc.
However some kept comminality with earlier 'Basic' airframes and had -9 engines.
Apologies, but cannot remember anything about power settings etc.