ITShop requiring a "Reason" parameter

I would like to create a service item that requires the requester to enter a "Reason" for the request.

I have created a Request Properties, with Reason as a mandatory parameter, and set this on the Service Item.  All seems to work as expected.

However, if I look at the "Additional information" in the shopping cart, I see two identical copies of the "Reason" field. Similarly, I see two identical copies in the request history.

Is there a way of doing this, or must I use other fields, such as "Additional information" instead?  For this case it's not too much a problem, but I would also like to force a "Valid until", and this is more of an issue.