ROF is ROF, rate of fire, BY DEFINITION means number of shots/rounds over a set of time. Since gauss ALWAYS uses 5 seconds as the time interval ROF means shots/rounds per 5 seconds. The fact that it is used wrongly in parts of the game makes no difference.
A musket or a howitzer has a ROF of 3 rounds per minute.
A Machine Gun has a ROF of 300 rounds per minute
A MLRS has a ROF of 1 round per 10 seconds
A SCUD has a ROF of 1 round per 8 hours.
A weapon which can fire 4 shots in 5 seconds has a ROF of 4 per 5 seconds
A weapon which can fire 1 shot every 15 seconds has a ROF of 1/3 per 5 seconds