On the one hand, units (teams) with 50%+ casualties are "disbanded":
Any infantry unit that has 50% or more of its soldiers killed or seriously wounded is disbanded, and its survivors are either sent to other units or rotated to the rear. Infantry units that take less than the 50% losses are assumed to find replacement men from disbanded infantry units or from new men brought up from the rear.
On the other hand, units (teams) with 50%+ casualties are "returned to the forcepool":
After a battle, units with less than 50% personnel strength are automatically returned to the Forcepool, and their soldiers are used to fill out losses in other teams. If enough soldiers from low strength teams are left over (i.e. not needed to fill out other units in the Battle Group) they are grouped together to form reduced strength teams (4 man ad-hoc / ersatz rifle teams, or 2 man light machine gun teams) that are added to your Forcepool automatically.
In the example shown below, the lone survivor of an Ersatz team is paired with one of the two survivors of a Grenadiere team to form a "reduced strength" Ersatz team of two, not four. The other Grenadiere survivor "was sent" as a "replacement" to become the third man in a Zugtruppe team that had taken two casualties. The Grenadiere team that lost 3 out of 5 was "disbanded" not "returned to the Forcepool". The sole survivor of a Grenadiere (MG) team was "rotated to the rear" rather than being used to "fill out" the 3-man Zugtruppe.
