diff --git a/lib/tiles/dbStore.js b/lib/tiles/dbStore.js
index 71ccd74..2b95549 100644
--- a/lib/tiles/dbStore.js
+++ b/lib/tiles/dbStore.js
@@ -190,12 +190,12 @@ define(["tiles/phoneGapConnector"],function(phonegap)
         }
 
         /**
-         * Provides a rough, approximate size of database in MBs.
+         * Provides the size of database in bytes
          * @param callback callback(size, null) or callback(null, error)
          */
         this.size = function(callback){
             if(this._db != null){
-                var usage = { size: 0, tileCount: 0 };
+                var usage = { sizeBytes: 0, tileCount: 0 };
 
                 var transaction = this._db.transaction(["tilepath"])
                     .objectStore("tilepath")
@@ -206,12 +206,11 @@ define(["tiles/phoneGapConnector"],function(phonegap)
                     if(cursor){
                         var storedObject = cursor.value;
                         var json = JSON.stringify(storedObject);
-                        usage.size += this.stringBytes(json);
+                        usage.sizeBytes += this.stringBytes(json);
                         usage.tileCount += 1;
                         cursor.continue();
                     }
-                    else{
-                        usage.size = Math.round(usage.size/1024/1024); /* JAMI: *2 */
+                    else{                        
                         callback(usage,null);
                     }
                 }.bind(this);
@@ -224,9 +223,8 @@ define(["tiles/phoneGapConnector"],function(phonegap)
             }
         }
 
-        this.stringBytes = function(str) {
-            var m = encodeURIComponent(str).match(/%[89ABab]/g);
-            return str.length + (m ? m.length : 0);
+        this.stringBytes = function(str) {            
+            return str.length /**2*/ ;
         }
 
         this.init = function(callback)
diff --git a/lib/tiles/offlineEnabler.js b/lib/tiles/offlineEnabler.js
index af00238..02263ca 100644
--- a/lib/tiles/offlineEnabler.js
+++ b/lib/tiles/offlineEnabler.js
@@ -29,13 +29,7 @@ define([
 			{
                 console.log("extending layer", layer.url);
 
-                layer._tileUrlArr = [];
-                layer._tileSize = 0;
-
-                //Reset _tileUrlArr when extent is changed
-                layer._map.on("update-start",function(evt){
-                    layer._tileUrlArr = [];
-                })
+                layer._lastTileUrl = "";                
 
                 /* we add some methods to the layer object */
 				/* we don't want to extend the tiled layer class, as it is a capability that we want to add only to one instance */
@@ -61,8 +55,7 @@ define([
 					if( this.offline.online )
 					{
                         console.log("fetching url online: ", url);
-                        layer._tileUrlArr.push(url);
-                        console.log("tile url " + layer._tileUrlArr.length)
+                        layer._lastTileUrl = url;
 						return url;
 					}
 
@@ -295,8 +288,8 @@ define([
                  */
 				layer.estimateTileSize = function(callback)
 				{
-                    if(layer._tileUrlArr.length > 0){
-                        var url = this.offline.proxyPath + "?" +  layer._tileUrlArr[0];
+                    if(layer._lastTileUrl){
+                        var url = this.offline.proxyPath + "?" +  layer._lastTileUrl;
                         request.get(url,{
                             handleAs: "text/plain; charset=x-user-defined",
                             headers: {
@@ -309,9 +302,8 @@ define([
                             });
                     }
                     else{
-                        return NaN;
+                        callback(NaN);
                     }
-
 				};
 
 				layer.doNextTile = function(i, cells, reportProgress)
diff --git a/samples/tiles/tiles-indexed-db.js b/samples/tiles/tiles-indexed-db.js
index 7fdaa87..60b4e76 100644
--- a/samples/tiles/tiles-indexed-db.js
+++ b/samples/tiles/tiles-indexed-db.js
@@ -172,8 +172,8 @@ require(["esri/map",
 			basemapLayer.getOfflineUsage(function(usage)
 			{
 				console.log(usage);
-				console.log("Avg tile size:", Math.round(usage.size * 1024 / usage.tileCount * 100) / 100, "Kb");
-				var usageStr = usage.size + " Mb (" + usage.tileCount + " tiles)";
+				console.log("Avg tile size:", Math.round(usage.sizeBytes / 1024 / usage.tileCount * 100) / 100, "Kb");
+				var usageStr = Math.round(usage.sizeBytes/1024/1024*100)/100 + " Mb (" + usage.tileCount + " tiles)";
 				dojo.byId('offline-usage').innerHTML = usageStr;
 			});
 		}
diff --git a/test/spec/offlineEnablerSpec.js b/test/spec/offlineEnablerSpec.js
index 622d385..a61b53c 100644
--- a/test/spec/offlineEnablerSpec.js
+++ b/test/spec/offlineEnablerSpec.js
@@ -115,6 +115,7 @@ describe("offline enabler library", function()
 		{			
 			g_basemapLayer.deleteAllTiles(function(success)
 			{
+				expect(success).toEqual(true);
 				var extent = new Extent({"xmin":-822542.2830377579,"ymin":4580841.761960262,"xmax":94702.05638410954,"ymax":5131188.365613382,"spatialReference":{"wkid":102100}});
 				var callCount = 0;
 				var reportProgress = function(progress)