Both Sympathy constraints and OO-correspondence constraints are
 types of correspondence constraints, and both can induce opaque
 phenomena. Yet, Sympathetic constraint interaction is mediated by a
 special type of correspondence constraints (cumulativity constraints),
 while OO-correspondence is mediated by ordinary correspondence
 constraints. This paper argues that cumulative constraints can also be
 used in OO-correspondence. It is also argued that this is desirable for
 two reasons: (i) It unifies these two kinds of non-IO-correspondence.
 (ii) Certain types of OO-correspondence induced opacity that are
 possible with ordinary correspondence constraints, are excluded if
 cumulative constraints are used. Cumulative OO-correspondence
 constraints therefore result in a more restrictive theory.