Yes, it is a good interpretation, but as you said, IMHO it is very interesting because it is an Attack Column, it is very useful approachig the enemy lines, with the impetus of the German 'boarhead', the Roman ordered steady pass, and the defense offered by the first two or three ranks using their shields like in the 'testudo', and we must remember that the rear ranks could also fire at the enemies! So better than the phalanx, more aggressive than the Testudo and more ordered than the Boarhead.
In my opinion they used frequently the Fulcum against enemies like the Persians, with all those horse archers!