| private decrease_subtotal ( float $amount ) : void | ||
| $amount | float | The amount to decrease the payment subtotal by. |
| return | void | |
private function decrease_subtotal($amount = 0.0)
{
$amount = (double) $amount;
$this->subtotal -= $amount;
if ($this->subtotal < 0) {
$this->subtotal = 0;
}
$this->recalculate_total();
}