GetOrdersEx and Mode of Sale issue

Hi,
I'm trying to list all the orders that belong to a constituent. In the API Documentation it says:

Normal 0 false false false EN-US X-NONE X-NONE "If not filtering results by mode of sale pass 0."

However, when I do this I only get back the orders that have the Web type  MOS. I've updated it to other MOS's and they then they do not show up.

I've also tried passing in other MOS's and it still lists them when they are the Web type.

Here's my call:

var response = GetSoapApi().GetOrdersEx(
                new Common().GetSessionKey(),
                0,
                String.Empty,
                'N',
                "2010-10-13",
                "2013-10-13",
                0,
                constituentID,
                0, // this is ModeOfSale filter
                'N',
                0
                );

Is there something I'm overlooking?

Thanks

- Kris