THANK YOU!

Thank you for your feedback.

The following cord is the hint,
the user who isn’t “Administrator” will be able to edit “scheduler for administrator”.

add_filter( 'attmgr_can_edit_admin_scheduler', 'my_filter', 99, 2 );
function my_filter( $result, $user ) {
	global $current_user;
	if ( ! $result ) {
		if ( current_user_can( 'editor' ) ) {
			$result = true;
		}
	}
	return $result;
}

Thank you tnomi, but can you please schedule this feature as an option? For future versions.

Thank you.
I wish to keep this simple without adding options as much as possible.
But I would like to prepare hooks so that each user can customize this easily.