That is happening because you still have this line in your cart customization code on that page:
ejejc_jQuery("#tdPmnt").attr("innerHTML", "Inserisci il prezzo che desideri pagare. </br> Il minimo è 1€ per sostenere alcuni costi di gestione.");
To clarify what's going on here:
Normally, the #tdPmnt element in the cart just says "Checkout:", but when the cart holds any editable-price items, we change the contents of that element to add an explanation about editing prices. However, when you customize the contents of #tdPmntt, that overrides anything we'd otherwise display in there, regardless of whether the cart contains editable-price items or not.
There doesn't appear to be any way to customize the price-editing explanation ONLY when the cart contains editable-price items. Using jQuery("b[style*='DAEA89']")...etc. ought to work for this, but doesn't for some reason; perhaps the version of jQuery our cart uses was too old to support that or had a bug. Since you're using ejejc_jQuery statements for cart customization, your site must be loading its own (probably more recent) version of jQuery, so you might try using that rather than our cart's version, in a separate SCRIPT block like so:
<script type="text/javascript">
$("b[style*='DAEA89']").attr("innerHTML","Custom stuff here");
</script>