In the AC_data.ini remove the "AHM" entries from stationID 18 and 19, thats what causes 4 amraams to show up.
In the loadout.ini change
Loadout[18].WeaponType=AIM-120C-5 ----> Loadout[20]
Loadout[18].Quantity=1 ----> Loadout[20]
Loadout[19].WeaponType=AIM-120C-5 ----> Loadout[21]
Loadout[19].Quantity=1 ----> Loadout[20]
As those are your AHM only stations.
Alternatively remove stations 20/21 and have the ahm on station18/19 with the IRM-s
Side note: loadlimit 3500kg is a bit unrealistic for a 500kg type pylon with IRM/AHM loads...
Side note2: stationID8/9 seem to be none existent in yout data.ini, also keep in mind that the stationID-s should be seqential, not 1,28,2,3,5,6,7,10,11,etc