Bro i was also using amsoil for my aqua but i got to know that currently the signature series and other amsoil series are only for petrol engines. For deisel engines right now no one is importing Amsoil in Pakistan.
I had no issues in using amsoil as Oil change interval was long but right now mobil, shell, liqui moly and Valvoline all oil change interval is 5000 kms i think so i am also looking at the overall cost.