pp_express.php + coupon discount.

[chufrog]

OpenCart - v1.5.6

I have a webshop

• checkout product "A" with paypal express => no problem
• checkout prodcct "A" with paypal express + 40% discount coupon => a "A non well formed numeric value encountered in .." error throw on catalog/model/paypment/pp_express.php line 267

Potential problem (wait for your confirm):
on pp_express.php - line 261:
$item_total = number_format($item_total + $item_price, 2);

it call number_format on the $item_total repeatedly (within a foreach loop).
but number_format return a string, it cause lots of problem on the next iteration and mess up the result of $item_total.

Suggestion:
change line 261 from
$item_total = number_format($item_total + $item_price, 2);
to
$item_total = $item_total + $item_price;