diff --git a/les/lespay/client/requestbasket_test.go b/les/lespay/client/requestbasket_test.go
index 6e9e08dae5ab..7c5f87c618f1 100644
--- a/les/lespay/client/requestbasket_test.go
+++ b/les/lespay/client/requestbasket_test.go
@@ -94,6 +94,30 @@ func TestReqValueFactor(t *testing.T) {
 	checkF64(t, "reqValueFactor", rvf, 333.333, 1)
 }
 
+func TestNormalize(t *testing.T) {
+	for cycle := 0; cycle < 100; cycle += 1 {
+		// Initialize data for testing
+		valueRange, lower := 1000000, 1000000
+		ref := referenceBasket{basket: requestBasket{items: make([]basketItem, 10)}}
+		for i := 0; i < 10; i++ {
+			ref.basket.items[i].amount = uint64(rand.Intn(valueRange) + lower)
+			ref.basket.items[i].value = uint64(rand.Intn(valueRange) + lower)
+		}
+		ref.normalize()
+
+		// Check whether SUM(amount) ~= SUM(value)
+		var sumAmount, sumValue uint64
+		for i := 0; i < 10; i++ {
+			sumAmount += ref.basket.items[i].amount
+			sumValue += ref.basket.items[i].value
+		}
+		var epsilon = 0.01
+		if float64(sumAmount)*(1+epsilon) < float64(sumValue) || float64(sumAmount)*(1-epsilon) > float64(sumValue) {
+			t.Fatalf("Failed to normalize sumAmount: %d sumValue: %d", sumAmount, sumValue)
+		}
+	}
+}
+
 func TestReqValueAdjustment(t *testing.T) {
 	var s1, s2 serverBasket
 	s1.init(3)
diff --git a/les/lespay/client/timestats_test.go b/les/lespay/client/timestats_test.go
index f3ee3771585e..a28460171e60 100644
--- a/les/lespay/client/timestats_test.go
+++ b/les/lespay/client/timestats_test.go
@@ -25,6 +25,25 @@ import (
 	"github.com/ethereum/go-ethereum/les/utils"
 )
 
+func TestTransition(t *testing.T) {
+	var epsilon = 0.01
+	var cases = []time.Duration{
+		time.Millisecond, minResponseTime,
+		time.Second, time.Second * 5, maxResponseTime,
+	}
+	for _, c := range cases {
+		got := StatScaleToTime(TimeToStatScale(c))
+		if float64(got)*(1+epsilon) < float64(c) || float64(got)*(1-epsilon) > float64(c) {
+			t.Fatalf("Failed to transition back")
+		}
+	}
+	// If the time is too large(exceeds the max response time.
+	got := StatScaleToTime(TimeToStatScale(2 * maxResponseTime))
+	if float64(got)*(1+epsilon) < float64(maxResponseTime) || float64(got)*(1-epsilon) > float64(maxResponseTime) {
+		t.Fatalf("Failed to transition back")
+	}
+}
+
 var maxResponseWeights = TimeoutWeights(maxResponseTime)
 
 func TestValue(t *testing.T) {
diff --git a/les/lespay/client/valuetracker.go b/les/lespay/client/valuetracker.go
index a7f732f0a78d..a770e553fdac 100644
--- a/les/lespay/client/valuetracker.go
+++ b/les/lespay/client/valuetracker.go
@@ -50,8 +50,6 @@ type NodeValueTracker struct {
 	basket               serverBasket
 	reqCosts             []uint64
 	reqValues            *[]float64
-
-	lastReqCosts []uint64 // accessed by ValueTracker only
 }
 
 // init initializes a NodeValueTracker.
@@ -60,7 +58,6 @@ type NodeValueTracker struct {
 func (nv *NodeValueTracker) init(now mclock.AbsTime, reqValues *[]float64) {
 	reqTypeCount := len(*reqValues)
 	nv.reqCosts = make([]uint64, reqTypeCount)
-	nv.lastReqCosts = nv.reqCosts
 	nv.lastTransfer = now
 	nv.reqValues = reqValues
 	nv.basket.init(reqTypeCount)
@@ -424,7 +421,6 @@ func (vt *ValueTracker) UpdateCosts(nv *NodeValueTracker, reqCosts []uint64) {
 	vt.lock.Lock()
 	defer vt.lock.Unlock()
 
-	nv.lastReqCosts = reqCosts
 	nv.updateCosts(reqCosts, &vt.refBasket.reqValues, vt.refBasket.reqValueFactor(reqCosts))
 }
 
@@ -454,7 +450,7 @@ func (vt *ValueTracker) periodicUpdate() {
 	vt.refBasket.normalize()
 	vt.refBasket.updateReqValues()
 	for _, nv := range vt.connected {
-		nv.updateCosts(nv.lastReqCosts, &vt.refBasket.reqValues, vt.refBasket.reqValueFactor(nv.lastReqCosts))
+		nv.updateCosts(nv.reqCosts, &vt.refBasket.reqValues, vt.refBasket.reqValueFactor(nv.reqCosts))
 	}
 	vt.saveToDb()
 }