Unable to scroll vertically UIScrollView/UITableView of ChildViewController if scrolling of UIScrollView of parent class is disabled forcefully

Question

AIM: To achieve the scroll of parent upto a particular point. Freeze its scroll and let the child view scroll till the bottom. Again move up, let child view controller scroll, till it reaches its top then let the parent view scroll till it reaches top and page comes to original state.

I am adding any childviewcontroller like this:

- (void)switchCurrentControllerWith:(UIViewController*)viewController andViewHeight:(float)height{

//1. The current controller is going to be removed
[selectedViewController willMoveToParentViewController:nil];
//    ((DRBaseViewController *)viewController).hideNavBar = YES;

//2. The new controller is a new child of the container
[self addChildViewController:viewController];

//3. Setup the new controller's frame depending on the animation you want to obtain
viewController.view.frame = containerRect;

//The transition automatically removes the old view from the superview and attaches the new controller's view as child of the
//container controller's view

[self transitionFromViewController:selectedViewController
                  toViewController:viewController
                          duration:0.1
                           options:UIViewAnimationOptionShowHideTransitionViews|UIViewAnimationOptionTransitionCrossDissolve
                        animations:^{


                        } completion:^(BOOL finished) {
                            //Remove the old view controller
                            [selectedViewController removeFromParentViewController];

                            //Set the new view controller as current
                            selectedViewController = viewController;
                            [selectedViewController didMoveToParentViewController:self];
                            [self.view bringSubviewToFront:navigationBar];

                             [self.scrollView setContentSize:CGSizeMake(320., CGRectGetMaxY(segmentedControl.frame) + height)];
                        }];
}

Now, there is a UIScrollView scaled to fit view height (504) in the parent view controller. I am doing following tasks in scrollview delegate methods for disabling the parent's scrollview and enabling the scroll of childviewcontroller's scrollview/tableview : -(void)scrollViewDidScroll:(UIScrollView*)scrollView {

if (scrollView.contentOffset.y >= self.segmentScrollView.frame.origin.y) {
    scrollView.scrollEnabled = NO;
    for (UIViewController *selectedViewController in containedControllers) {
        for (UIView *view in selectedViewController.view.subviews) {
            if ([view isKindOfClass:[UITableView class]]) {
                UITableView *tableView = (UITableView*)view;
                tableView.scrollEnabled = YES;
            }
            else if ([view isKindOfClass:[UIScrollView class]]){
                UIScrollView *scrollView = (UIScrollView *)view;
                scrollView.scrollEnabled = YES;
            }
        }
    }

}
else{
    for (UIViewController *selectedViewController in containedControllers) {
        for (UIView *view in selectedViewController.view.subviews) {
            if ([view isKindOfClass:[UITableView class]]) {
                UITableView *tableView = (UITableView*)view;
                tableView.scrollEnabled = NO;
            }
            else if ([view isKindOfClass:[UIScrollView class]]){
                UIScrollView *scrollView = (UIScrollView *)view;
                scrollView.scrollEnabled = NO;
            }
        }
    }
}

if ([scrollView isAtBottom]) {

    for (UIView *view in selectedViewController.view.subviews) {
        if ([view isKindOfClass:[UITableView class]]) {
            UITableView *tableView = (UITableView*)view;
            tableView.scrollEnabled = YES;
        }
        else if ([view isKindOfClass:[UIScrollView class]]){
            UIScrollView *scrollView = (UIScrollView *)view;
            scrollView.scrollEnabled = YES;
        }
    }
}
}

Now my PROBLEM IS THE CHILDVIEW'S SCROLL/TABLEVIEW is not getting scrolled when the parent's scrollview reaches a fixed content offset and then the childview's scrollview have to be scrolled! What seems to be the problem here?

PS. I checked the childview's Scroll/TableView's frame and content Size and that is not an issue.

NOTE: I see the scrolling of my child view's table/scrollview has been disabled in one direction and is enabled in another!