WATCH OUT! Another Brain Storm...
This is just conjecture J, but the mounting angles may have had something to do with how the engine was installed in the chassis. You had MEL forward mount and mid mount models (engine supports) and the differences (angle fitting to keep the supply tube closer to the engine) may be there.
One would need the first issues of the appropriate MPC as parts are superseceded (design change or obsoleted) (due to low demand), the catalog is usually updated to not show origional information.
To me, the angle mount would be more advantageous as it allows for less component vibration and chance of damage from running over something, say.