Just when I figure things out, they change it up.
post-2.2 SZ rules:
-When one team is in control, the other team builds special.
-When neither team is in control, the team that's in the lead builds special (but at a slower rate than above).
post-2.2 TC rules:
-When one team controls the tower, that team builds special. (opposite of the SZ rule)
-When neither team controls the tower, the losing team charges special. (again, opposite of the SZ rule)
-Special charge for all of these rules is slower than pre-2.2.