more distinction

diff --git a/skeletons/constr_SET_OF.c b/skeletons/constr_SET_OF.c
index 01328b4..eed604e 100644
--- a/skeletons/constr_SET_OF.c
+++ b/skeletons/constr_SET_OF.c
@@ -577,7 +577,8 @@
 				continue;
 			}
 			/* Fall through */
-		case XCT_UNEXPECTED:
+		case XCT_UNKNOWN_OP:
+		case XCT_UNKNOWN_BO:
 
 			ASN_DEBUG("XER/SET OF: tcv=%d, ph=%d", tcv, ctx->phase);
 			if(ctx->phase != 1)
@@ -595,8 +596,6 @@
 				 */
 				ctx->phase = 2;
 				continue;
-			case XCT_UNEXPECTED:
-			case XCT_CLOSING:
 			default:
 				break;	/* Phase out */
 			}