diff --git a/src/specificClass.js b/src/specificClass.js
index cd78b67..bf98c45 100644
--- a/src/specificClass.js
+++ b/src/specificClass.js
@@ -283,6 +283,18 @@ class MachineGroup {
 
         this.logger.debug(`Dynamic Totals after pressure change - Flow: Min ${flow.min}, Max ${flow.max}, Act ${flow.act} | Power: Min ${power.min}, Max ${power.max}, Act ${power.act}`);
         this._writeMeasurement("flow", "predicted", POSITIONS.AT_EQUIPMENT, flow.act, this.unitPolicy.canonical.flow);
+        // Mirror the aggregate flow onto DOWNSTREAM as well. PS subscribes to
+        // flow.predicted.downstream from MGC and uses it as the outflow
+        // estimate for net-flow computation. Without this mirror, the only
+        // place DOWNSTREAM gets written is optimalControl's bestFlow (the
+        // optimizer's TARGET, not the achieved aggregate). During transients
+        // — e.g. demand dropping to dead-band keep-alive while pumps are
+        // still ramping down from full throttle — PS would see a stale
+        // 25 m³/h target while pumps are physically delivering 500+ m³/h,
+        // making netFlow look small and stable when the basin is actually
+        // draining fast. flow.act here is the sum of every pump's current
+        // predicted output, so it IS the achieved aggregate.
+        this._writeMeasurement("flow", "predicted", POSITIONS.DOWNSTREAM, flow.act, this.unitPolicy.canonical.flow);
         this._writeMeasurement("power", "predicted", POSITIONS.AT_EQUIPMENT, power.act, this.unitPolicy.canonical.power);
 
         const { maxEfficiency, lowestEfficiency } = this.calcGroupEfficiency(this.machines);