diff --git a/engine/calldesc.go b/engine/calldesc.go
index ceca357bc..817b3ce86 100644
--- a/engine/calldesc.go
+++ b/engine/calldesc.go
@@ -368,6 +368,11 @@ func (cd *CallDescriptor) roundTimeSpansToIncrement(timespans TimeSpans) []*Time
 	return timespans
 }
 
+// Returns call descripor's total duration
+func (cd *CallDescriptor) GetDuration() time.Duration {
+	return cd.TimeEnd.Sub(cd.TimeStart)
+}
+
 /*
 Creates a CallCost structure with the cost information calculated for the received CallDescriptor.
 */
diff --git a/sessionmanager/fssessionmanager.go b/sessionmanager/fssessionmanager.go
index fcc10e50d..677a0ec3e 100644
--- a/sessionmanager/fssessionmanager.go
+++ b/sessionmanager/fssessionmanager.go
@@ -310,10 +310,8 @@ func (sm *FSSessionManager) OnChannelHangupComplete(ev Event) {
 
 }
 
-func (sm *FSSessionManager) LoopAction(s *Session, cd *engine.CallDescriptor, index float64) (cc *engine.CallCost) {
+func (sm *FSSessionManager) LoopAction(s *Session, cd *engine.CallDescriptor) (cc *engine.CallCost) {
 	cc = &engine.CallCost{}
-	cd.LoopIndex = index
-	cd.CallDuration += sm.debitPeriod
 	err := sm.connector.MaxDebit(*cd, cc)
 	if err != nil {
 		engine.Logger.Err(fmt.Sprintf("Could not complete debit opperation: %v", err))
diff --git a/sessionmanager/session.go b/sessionmanager/session.go
index 2af31f6f8..40b57cc42 100644
--- a/sessionmanager/session.go
+++ b/sessionmanager/session.go
@@ -77,6 +77,7 @@ func NewSession(ev Event, sm SessionManager) (s *Session) {
 func (s *Session) startDebitLoop() {
 	nextCd := *s.callDescriptor
 	index := 0.0
+	debitPeriod := s.sessionManager.GetDebitPeriod()
 	for {
 		select {
 		case <-s.stopDebit:
@@ -86,9 +87,14 @@ func (s *Session) startDebitLoop() {
 		if index > 0 { // first time use the session start time
 			nextCd.TimeStart = nextCd.TimeEnd
 		}
-		nextCd.TimeEnd = nextCd.TimeStart.Add(s.sessionManager.GetDebitPeriod())
-		cc := s.sessionManager.LoopAction(s, &nextCd, index)
-		nextCd.TimeEnd = cc.GetEndTime()
+		nextCd.TimeEnd = nextCd.TimeStart.Add(debitPeriod)
+		nextCd.LoopIndex = index
+		nextCd.CallDuration += debitPeriod // first presumed duration
+		cc := s.sessionManager.LoopAction(s, &nextCd)
+		nextCd.TimeEnd = cc.GetEndTime() // set debited timeEnd
+		// update call duration with real debited duration
+		nextCd.CallDuration -= debitPeriod
+		nextCd.CallDuration += nextCd.GetDuration()
 		time.Sleep(cc.GetDuration())
 		index++
 	}
diff --git a/sessionmanager/sessionmanager.go b/sessionmanager/sessionmanager.go
index 9eb2f68ae..ea0074786 100644
--- a/sessionmanager/sessionmanager.go
+++ b/sessionmanager/sessionmanager.go
@@ -19,16 +19,17 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>
 package sessionmanager
 
 import (
+	"time"
+
 	"github.com/cgrates/cgrates/config"
 	"github.com/cgrates/cgrates/engine"
-	"time"
 )
 
 type SessionManager interface {
 	Connect(*config.CGRConfig) error
 	DisconnectSession(*Session, string)
 	RemoveSession(*Session)
-	LoopAction(*Session, *engine.CallDescriptor, float64) *engine.CallCost
+	LoopAction(*Session, *engine.CallDescriptor) *engine.CallCost
 	GetDebitPeriod() time.Duration
 	GetDbLogger() engine.LogStorage
 	Shutdown() error