Device rotaion issue - iphone

Question

I detect screen change orientation with :
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(detectOrientation) name:#"UIDeviceOrientationDidChangeNotification" object:nil];
and when it call i call this method:
if(orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown) {
[md changeToBigNowPlaying:YES withLayer:avPlayerLayer];
}else{
[md changeToBigNowPlaying:NO withLayer:avPlayerLayer];
}
and in this function i do this stuff:
-(void)changeToBigNowPlaying:(BOOL)flag withLayer:(AVPlayerLayer*)layer{
if (flag) {
//To portrait
[landVC.view removeFromSuperview];
[layer removeFromSuperlayer];
[self.window addSubview:tab.view];
}else {
//To landscape
[tab.view removeFromSuperview];
[landVC setUpNewLayer:layer];
[self.window addSubview:landVC.view];
}
}
and this is the explanation :
I have tabbar with viewcontroller,and when i detect that the user rotate the screen to landscape i remove the tabbar and add a UIViewController(landVC) and when i rotate it to portrait again i remove the landvc and add again the tabbar.
my problem is when i rotate first to UIInterfaceOrientationLandscapeLeft so it show me the screen in UIInterfaceOrientationLandscapeRight. but when i rotate to UIInterfaceOrientationLandscapeRight first i see the screen like it should and when i rotate from this situation to UIInterfaceOrientationLandscapeLeft i see the screen good too.
any idea why i have a problem when i rotate to UIInterfaceOrientationLandscapeLeft and i see the landVc in UIInterfaceOrientationLandscapeRight
In landVC UIViewController i implement:
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
if(interfaceOrientation == UIInterfaceOrientationLandscapeRight){
return YES;
}else if (interfaceOrientation == UIInterfaceOrientationLandscapeLeft) {
return YES;
}else {
return NO;
}
}
Edit
-(void)detectOrientation{
UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];
if(orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown) {
[md changeToBigNowPlaying:YES withLayer:avPlayerLayer];
}
if(orientation == UIInterfaceOrientationLandscapeRight || orientation == UIInterfaceOrientationLandscapeLeft) {
[md changeToBigNowPlaying:NO withLayer:avPlayerLayer];
}
}