Hi Christine,
Thanks for the welcome! I went over to StackExchange/StackOverflow to ask for ideas and found a solution:
In the cart.php file’s get_cart_value() function:
public function get_cart_value(){
$cart = $this->cart;
$prices = array();
$cart = apply_filters('ss_mod_cart_value', $cart);
foreach ($cart as $product){
array_push( $prices, array('price'=>trim($product), 'discount' => trim($product )));
}
$total = 0;
foreach($prices as $price){
$price = $this->calc_discount($price, $price);
//$price = str_replace('.', '', $price);
$price = floatval(preg_replace('/[^d.]/', '' , $price));
$total += $price;
}
//$total = number_format($total/100, 2);
$total = number_format($total, 2);
return $total;
}
I replaced the string conversion to float and changed the total to fit the number of decimal places. Now the cart displays the 4-digit values correctly 
Here is the thread I started at StackExchange:
http://stackoverflow.com/questions/22979537/displaying-currency-values-greater-than-1000
The thread I used for reference:
http://stackoverflow.com/questions/5139793/php-unformat-money
Hope this will be helpful to someone else looking for a solution while waiting for the big new version (Symbio 3.4? 4.0?
)