EFC of 6000 on a 150k salary with no other kids in college, seems unbelievable, no wonder your ‘friends’ commented.
Make sure the numbers entered on CSS Profile are correct.
Does your son have a lot of research experience ? DS received a generous stipend for research, and since we did not qualify for any need based aid, it was paid for summers only i.e. paid summer research grant. However, if we were eligible for need based aid, then the EFC would have been reduced by a quite a bit.
It is possible that you received a merit and need based aid.
Just make sure that the grants you received is for all 4 years, before you commit.