Cache size

Hello,
I had a problem, every 2/3 days the size of the cache reached the limit and the status was colored in red. I was therefore advised to add this code to the function.php file

//* Automatically cache dimensions
add_filter('autoptimize_filter_cachecheck_maxsize','change_maxsize');
	function change_maxsize() {
	return 1*1024*1024*1024;
}

//* Automatically clear Autoptimize cache if it goes beyond 2GB
if (class_exists('autoptimizeCache')) {
    $myMaxSize = 950000; # You may change this value to lower like 500000 for 500MB if you have limited server space
    $statArr=autoptimizeCache::stats(); 
    $cacheSize=round($statArr[1]/1024);   
    if ($cacheSize>$myMaxSize){
       autoptimizeCache::clearall();
       header("Refresh:0"); # Refresh the page so that autoptimize can create new cache files and it does breaks the page after clearall.
     }
}

Initially, everything seemed ok, and therefore the size of the available cache had increased.

I realize instead that it is only a graphic feedback, but in reality the dimensions are limited to 500mb. In fact Autoptimaze never rises above this threshold. Where am I wrong?