diff --git a/bar.go b/bar.go
index f364b46..de6c89c 100644
--- a/bar.go
+++ b/bar.go
@@ -78,6 +78,7 @@
 	mDecorators       []decor.Decorator
 	amountReceivers   []decor.AmountReceiver
 	shutdownListeners []decor.ShutdownListener
+	averageAdjusters  []decor.AverageAdjuster
 	bufP, bufB, bufA  *bytes.Buffer
 	bufE              *bytes.Buffer
 
@@ -186,18 +187,15 @@
 // AdjustAverageDecorators updates start time of all average decorators.
 // Useful for resume-able tasks.
 func (b *Bar) AdjustAverageDecorators(startTime time.Time) {
-	type adjustable interface {
-		AverageAdjust(time.Time)
-	}
-	b.UpdateDecorators(func(d decor.Decorator) {
-		if d, ok := d.(adjustable); ok {
-			d.AverageAdjust(startTime)
-		}
-	})
-}
-
-// UpdateDecorators general helper func.
-func (b *Bar) UpdateDecorators(cb decor.UpdateFunc) {
+	b.operateState <- func(s *bState) {
+		for _, adjuster := range s.averageAdjusters {
+			adjuster.AverageAdjust(startTime)
+		}
+	}
+}
+
+// TraverseDecorators traverses all available decorators and calls cb func on each.
+func (b *Bar) TraverseDecorators(cb decor.CBFunc) {
 	b.operateState <- func(s *bState) {
 		for _, decorators := range [...][]decor.Decorator{
 			s.pDecorators,
diff --git a/decor/decorator.go b/decor/decorator.go
index 92c8e49..2f941d7 100644
--- a/decor/decorator.go
+++ b/decor/decorator.go
@@ -93,10 +93,17 @@
 	Shutdown()
 }
 
-// UpdateFunc convenience func type
-type UpdateFunc func(Decorator)
+// AverageAdjuster interface.
+// Average decorators should implement this interface to provide start
+// time adjustment facility, for resume-able tasks.
+type AverageAdjuster interface {
+	AverageAdjust(time.Time)
+}
 
-// Global convenience shortcuts
+// CBFunc convenience call back func type.
+type CBFunc func(Decorator)
+
+// Global convenience instances of WC with sync width bit set.
 var (
 	WCSyncWidth  = WC{C: DSyncWidth}
 	WCSyncWidthR = WC{C: DSyncWidthR}
diff --git a/progress.go b/progress.go
index 6bd49e1..c01e5ca 100644
--- a/progress.go
+++ b/progress.go
@@ -146,18 +146,23 @@
 	}:
 		var amountReceivers []decor.AmountReceiver
 		var shutdownListeners []decor.ShutdownListener
+		var averageAdjusters []decor.AverageAdjuster
 		bar := <-result
-		bar.UpdateDecorators(func(d decor.Decorator) {
+		bar.TraverseDecorators(func(d decor.Decorator) {
 			if d, ok := d.(decor.AmountReceiver); ok {
 				amountReceivers = append(amountReceivers, d)
 			}
 			if d, ok := d.(decor.ShutdownListener); ok {
 				shutdownListeners = append(shutdownListeners, d)
+			}
+			if d, ok := d.(decor.AverageAdjuster); ok {
+				averageAdjusters = append(averageAdjusters, d)
 			}
 		})
 		bar.operateState <- func(s *bState) {
 			s.amountReceivers = amountReceivers
 			s.shutdownListeners = shutdownListeners
+			s.averageAdjusters = averageAdjusters
 		}
 		return bar
 	case <-p.done: