Post Modified Time

Hi !

I want to display the_modified_date next to the_date (in the loop or in single), only if the post was modified, and more than 3 hours after its published time.

I usually use something like this directly on single.php :

<?php
define ('DELAY_POST_UPDATE_DISPLAY', 3);
if (get_the_modified_date() != get_the_date() || get_the_modified_time('Gi') - get_the_time('Gi') >= DELAY_POST_UPDATE_DISPLAY * 100) :
?>
    <time datetime="<?php the_modified_time('c');?>"><?php the_modified_time('j F Y \à H:i'); ?></time>
<?php
endif;
?>

…but for some kind of reason, I don’t succeed to implement it well, either in single.php or using function.php. The modified time appears all the time, even is the post hasn’t be modified. I have to say I’m not a php developer, I don’t know if I did the thing right, but i succeed on three other themes, and not in this one =/

I know i have to modify the highwind_post_date in functions.php. This is how far i get without breaking the theme (and without the “if” statement)

// custom post date and modified time
if ( ! function_exists( 'highwind_post_date' ) ) {
	function highwind_post_date() {
		if ( ! is_page() && ! is_404() ) {
		?>
			<time datetime="<?php the_time('c');?>" class="post-date"><a 

href="<?php the_permalink(); ?>" title="<?php printf( esc_attr__( 'Permalink to %s', 'highwind' ), 

the_title_attribute( 'echo=0' ) ); ?>" rel="bookmark"><?php the_time( get_option( 'date_format' ) ); ?

></a></time>
			<time datetime="<?php the_modified_time('c');?>" class="post-

modified-date"><a href="<?php the_permalink(); ?>" title="<?php printf( esc_attr__( 'Permalink to %s', 

'highwind' ), the_title_attribute( 'echo=0' ) ); ?>" rel="bookmark"><?php the_modified_time( 

get_option( 'date_format' ) ); ?></a></time>

		<?php
		}
	}
}

Can you please help me on this ? ??

Thanks ! ??