AyeCode / invoicing

        return $note_id;

    }

    private function increase_subtotal( $amount = 0.00 ) {

        $amount          = (float) $amount;

        $this->subtotal += $amount;

        $this->subtotal  = wpinv_format_amount( $this->subtotal, NULL, true );

        $this->recalculate_total();

    }

    private function decrease_subtotal( $amount = 0.00 ) {

        $amount          = (float) $amount;

        $this->recalculate_total();

    }

    private function increase_fees( $amount = 0.00 ) {

        $amount            = (float)$amount;

        $this->fees_total += $amount;

        $this->fees_total  = wpinv_format_amount( $this->fees_total, NULL, true );

        $this->recalculate_total();

    }

    private function decrease_fees( $amount = 0.00 ) {

        $amount            = (float) $amount;