public function addAddition($value)
    {
        $this->data->amount->subtotals->addition += $this->convertAmount($value);

        return $this;
    }
public function addAddition($value)
    {
        $this->data->amount->subtotals->addition += $this->convertAmount($value);

        return $this;
    }
public function addAddition ( $ value ) { $ this -> data -> amount -> subtotals -> addition += $ this -> convertAmount ( $ value ) ; return $ this ; }
Add a value addition

@param  float  $value
@return $this
Add a value addition