diff --git a/nettests/nettests.go b/nettests/nettests.go
index ea06ade..2231546 100644
--- a/nettests/nettests.go
+++ b/nettests/nettests.go
@@ -76,6 +76,10 @@ func (c *Controller) Run(builder *engine.ExperimentBuilder, inputs []string) err
 	builder.SetCallbacks(model.ExperimentCallbacks(c))
 	c.numInputs = len(inputs)
 	exp := builder.NewExperiment()
+	defer func() {
+		c.res.DataUsageDown += exp.KibiBytesReceived()
+		c.res.DataUsageUp += exp.KibiBytesSent()
+	}()
 
 	c.msmts = make(map[int64]*database.Measurement)
 
@@ -202,6 +206,9 @@ func (c *Controller) OnProgress(perc float64, msg string) {
 
 // OnDataUsage should be called when we have a data usage update.
 func (c *Controller) OnDataUsage(dloadKiB, uploadKiB float64) {
-	c.res.DataUsageDown += dloadKiB
-	c.res.DataUsageUp += uploadKiB
+	// Unused as 2020-04-05: we're now using directly the accessors
+	// provided by the experiment. This callback is going to be removed
+	// from probe-engine in May or June.
+	//
+	// TODO(bassosimone): create an issue for this?
 }