There are 2 types of Miscellaneous:  Items and Charges.  Charges (type 2) do not have a quantity, price, etc. but do have an extension amount.  The Misc Items (type 5) work like regular items (type 1) for the most part but there are some exceptions.  Could you be using a Miscellaneous Charge perhaps?  What fields are being set when you are creating the order?

Thank you. I realized that the issue was resulting from trying to add quantities and pricing on comment and charge types of miscellaneous items