I was a few years ago on one container vessel with 3 radars - 2 above bridge and 1 fwd! According documentation fwd radar was with big "blind"spot sector aft to prevent radiation over accommodation and its primary target was to detect small crafts ahead of vessel as she was initiallyy designated to sail around/close to Japan.
Nowdays you may see on some "monster"container ships with radars on fwd mast + 2 or 3 above bridge + aft mast(below) exactly for that reason - similar to ferries, but main idea is to detect small crafts which the main radars cannot due to some cargo restrictions.
On that picture/link which you attacched - I believe the idea is the same - due to possible cargo obstruction is better to have "an eye" fwd ... and most probably has blind sector aft!
If the Class allows - why not .... even in some points is better if no have "side effects"