+ $self->{delivered_qty} = sum(map { AM->convert_unit($_->unit => $self->unit) * $_->qty } @doi_delivered);
+
+ return $self->{delivered_qty};
+}
+
+sub value_of_goods {
+ my ($self) = @_;
+
+ my $price_factor = $self->price_factor || 1;
+
+ $self->_delivered_qty;
+ return ($self->_delivered_qty * $self->sellprice * (1 - $self->discount ) / $price_factor);