well its a one way award
the chart says:
For one-way flights, the above-mentioned mileage values apply in half.
so iso 42000 it should be 21000 miles
So is aegean correct in saying that if I want AMS MUC FRA LNZ in stead of AMS FRA LNZ they will charge me double the miles
since other airlines would charge me only 20 000 miles for the same star alliance award trip