The structure of the infantry of the 256th Infantry Division on 2 March 1944 displays a somewhat lopsided character. Thanks to attachments, the two organic grenadier regiments of the formation (the 481st and 456th Grenadier Regiments) had become four-battalion outfits that were, relative to the times, well supplied with regimental heavy weapons. Thanks to detachments for the sake of the organic regiments, however, the two infantry units borrowed from other divisions (the 350th and 306th Grenadier Regiments) were much smaller. Each retained a single grenadier battalion, an understrength anti-tank company, and a depleted infantry gun company.
Each of the borrowed regiments received reinforcement in the form of battalions that, while rich in manpower, did not qualify, by the standards of the German Army of the day, as “infantry.” One of these was a construction unit. The other was a security battalion.
One possible explanation for the asymmetry in the layout of the 256th Infantry Division is the use of the two attached regiments as “small change.” Easily transferred from one sector to the other, the two two-battalion outfits allowed the commanding general of the division to adjust to minor changes in his situation without disrupting the defensive arrangements of the two large regiments.
Source: Barbara Selz, Das Grüne Regiment. Der Weg der 256. Infanterie-Division aus der Sicht des Regiments 481 (Freiburg im Breisgau: Verlag Otto Kehrer, 1970)