[Tuner]

OK This mod allow you to update you quantity relative to the current quantity. Tested on 4.0.13

If you check Relative update it will add to the quantity if the number is positive and subtract if the number is negative.

Find: (provider/inv_update.php)

		while ($columns = fgetcsv ($fp, 65536, $delimiter)) {
			if (empty($columns[0])) {
				continue;
			}
			$columns[0] = addslashes($columns[0]);
			$pid = func_query_first_cell ("SELECT productid FROM $sql_tbl[products] WHERE productcode='$columns[0]' $provider_condition");

Below this last line Add the following code:

			if (!empty($rel)){
			$pquan = func_query_first_cell ("SELECT avail FROM $sql_tbl[products] WHERE productcode='$columns[0]' $provider_condition");
			$pquan = $pquan + $columns[1];
			} else {
			$pquan = $columns[1];
			}

Now find (in provider/inv_update.tpl):

<TD>{$lng.lbl_csv_file}</TD>
<TD><INPUT type="file" name="userfile">

Make Look Like this:

<TD>{$lng.lbl_csv_file}</TD>
<TD><INPUT type="file" name="userfile">
<INPUT type="checkbox" name="rel">Relative Qauntity Change

Cheers