You will have to update the looping code for the cart display... currently it has something like:
<?php
while (!$eCart1->EOF()) {
?>
// cart rows here
<?php
$eCart1->MoveNext();
}
$eCart1->MoveFirst();
?>
you would replace it with code like:
<?php
$eCart1->MoveLast();
do {
?>
// cart rows here
<?php
$eCart1->MovePrevious();
} while (!$eCart1->BOF());
?>