Funny... must be bad luck on your end. I am in the same area around christmas 1940. Sank about 66,000 BRT of single merchants and out of one convoy (which also had a Fidji class cruiser... but my two last torps on that one didnt go off.
). I didnt see a single enemy aircraft all the time while I stayed there for like 3 weeks...
GWX 2.0 that is.