Priority conflict with custom metaboxes and built-in discussion metabox

I’m developing a premium theme and got a strange issue. I’m creating my custom meta boxes which have around 100 fields. I’m trying like this:

function page_options_metaboxes() {
$screens = array('post', 'page');
foreach( $screens as $screen) {
    add_meta_box( 'custom_page_options', 'Custom Page Options', 'page_options_callback', $screen, 'normal', 'high' );   }
}
add_action( 'add_meta_boxes', 'page_options_metaboxes' );

Notice the priority is “high”, if its high, default “Discussion metabox” doesn’t work/update. And if I set priority to low or default, Discussion metaboxes work fine, but then my custom fields work under limitations i.e. it will save around first 60 options, and remaining 40 don’t update.

Also I noticed when I set “context” to “side” for my metabox, then all options work fine. Not sure what’s going on crazy.

I would prefer that:
1. priority to be high for my Page Options metaboxes
2. all my custom metaboxes to work i.e. save/update
3. Discussion metaboxes should also work property.

Please help anybody and many thanks in advance…