diff --git a/FAC/FAC_PAC.SRC b/FAC/FAC_PAC.SRC
index 13529952..2b7b66b6 100644
--- a/FAC/FAC_PAC.SRC
+++ b/FAC/FAC_PAC.SRC
@@ -1745,9 +1745,11 @@ CREATE OR REPLACE PACKAGE BODY fac AS
                         (fac_perfmon_aantal, fac_perfmon_waarde,
                          fac_perfmon_datum, fac_perfmon_threshold
                         )
-                 VALUES (1, zwaarte,
+                 SELECT 1, zwaarte,
                          TRUNC (SYSDATE), limiet
-                        );
+                   FROM DUAL
+                      WHERE TRUNC (SYSDATE) NOT IN -- multi-user safe maken
+                        (SELECT fac_perfmon_datum FROM fac_perfmon);
       END;
    END;