That is fully correct. The other explanation is wrong. Only an unit perpendicular to the forward or backward direction of vehicle can either hit the front or the back. It is important to define what exactly things are relative to each other when defining perpendicular. Otherwise, it can be read as a shot coming perpendicular to the front of the vehicle hits either front or back - which is completely wrong.
This lovely old figure should help. It was taken approximately perpendicular to the moving direction of a vehicle, thus the chance of hitting front or back depends on other numerous values (in the most perfect case of ultimate perfection, it is a 50% chance to either hit front or back)
Note: there was one vehicle exception where this above generalisation is not true (Elefant 75% front, 25% back ) <- past tense.
Post has been edited after quote to clarify points.