comparing rates between 2 different cars- even the same generation model in different model years- is apples to oranges. The formulas used to calculate rates are so involved that it would take an actuary all day to adequately explain. Tiny differences get magnified when there are a few million units in use...lots of $$ at stake. Yes, the '03 probably tested slightly differently than the '04. Who knows why- numbers is numbers. Thus the seemingly "outrageous" differences that don't make sense on the surface to us.

Ask your company for a quote on the non-hybrid in the same trim level HCH, FEH, etc. That's the closest way to get a 2nd apple to compare.