Angle of shot into metal or auto glass not only affects trajectory and how the bullet impacts initially, but also increases the depth to be penetrated. It was the main reason why they sloped armor on tanks, if you hit something at a 30 degree angle it meant penetrating double the amount of the material, armor or otherwise. Things like armor plate can quadruple their protection when being doubled, and certain materials will gain more resistance in the same way (car sheet metal might resist a round more than 200% even if the actual extra material to pierce is technically 200% due to a 30 degree angle hit). Small changes can lead to massive differences in final performance in real life situations.
Add in changes to metalurgy of car doors, hardness of the particular factory swaged bullet you are firing, how "hot" your rounds are running in your particular service revolver, we cannot be surprised if real life experiences come back with vastly different outcomes. Ford Pinto or my Lincoln Mk5? As has been stated, glass is where during the shootout, rolled down leaves no protection in the windowed area but also means rounds through the door have to pierce through the door AND the window. Everything affects everything.
As for end performance. even high end modern hollow points are known for lack of expansion after punching through barriers, simply boils down to lack of power after punching through material. The FBI load probably would not either, of course. One could argue that the SJHP is superior in revolvers over JHP bullets, but modern JHP's are suggested for those who still carry them because the full jacket protects the hollow point from deformation when fired through solid barriers. In any case, I wouldn't count on them expanding.