Is there a way to add a sell quantity to an order other than the box quantity that is used for purchasing?
Yes, normally the box quantity field in the purchasing tab is what controls the purchasing and the sale default quantity for the product. To override the box quantity field on the sales order, there is a field called Selling Box Quantity on the product master.
To set a selling box quantity, navigate to File>Product>Master>Setup tab, Main subtab and click Edit. Enter the quantity you want the system to default in the sales order.
Ex: If you purchase in quantities of 50 but you sell them in quantities of 5 you would set this field to 5.
