Wake Turbulence Question

I was level at 1500' MSL and ATC announced a Gulfstream bizjet crossing from my
right to left, 3000' MSL less than a mile lateral distance. I had my
instrument student do a 360 for wake turbulence separation and dissipation.
ATC questioned my actions and told me the 360 wasn't necessary.

BTW: I was in Class Echo airspace in southern Maine.

I havent been instructing all that long but this did seem to me to be a classic
wake turb encounter in the making. I am interested in hearing from other
pilots and CFII's on this subject. Was I over cautious ? Or prudent.....


Hank