[orban]

You could try to replace

$fp = fopen($templatefile, 'w+');
if ($fp && flock($fp, LOCK_EX))
{
	fwrite($fp, '<?php '.$cache_to_save.' ?>');
	flock($fp, LOCK_UN);
	fclose($fp);
}

with

if (rand() < 0.1)
{
	$fp = fopen($templatefile, 'w+');
	if ($fp && flock($fp, LOCK_EX))
	{
		fwrite($fp, '<?php '.$cache_to_save.' ?>');
		flock($fp, LOCK_UN);
		fclose($fp);
	}
}

So basically a protection that only every 10th page call tries to write out the page.