Line item lookup

I am using fm 5 and have created an invoicing app. I have inv_hdr and inv_items tables related by invoice number. In my customer table, each customer has a discount level of 1-10. My products each have a price for each of these values 1-10. So if a customer who has discount level 3 is created an invoice for product "abc" the invoice lineitem would retrieve the price that is in retail3 from the products table and place it on the invoice line item. This all works well on the second and greater line items of the invoice, but not on the first line item. I have a relatively simple line item layout of "Qty, prodid, length, description, price, extended". I can fill in the header up to the point before I enter the lineitem portal, change to the previous record and then come back to the invoice and I can enter the first line item on the invoice and it will retreive the price of the lookedup product. However if I try and enter the complete invoice and line items, the product id and description are filled in the portal but no price. Following is my calculation in the field Inv_items:Price on which product price to retreive from the prodcuts table based on the customers discount level: (I have a field in the invoice header table called 'Price_leve' which allows for a manual overide of the default discount level on an invoice by invoice basis if the clerk so chooses.)

Case(Invoice_Header::PRICE_LEVE=1,Product::PRICE1,

Invoice_Header::PRICE_LEVE=2,Product::PRICE2,

Invoice_Header::PRICE_LEVE=3,Product::PRICE3,

Invoice_Header::PRICE_LEVE=4,Product::PRICE4,

Invoice_Header::PRICE_LEVE=5,Product::PRICE5,

Invoice_Header::PRICE_LEVE=6,Product::PRICE6,

Invoice_Header::PRICE_LEVE=7,Product::PRICE7,

Invoice_Header::PRICE_LEVE=8,Product::PRICE8,

Invoice_Header::PRICE_LEVE=9,Product::PRICE9,

Invoice_Header::PRICE_LEVE=10,Product::PRICE10,"")

Thanks

One more comment, I have a button on the invoice which runs a script to refresh the current window. If I click this button before I enter the portal the first line item seems to lookup and retrieve the product price. I was just hoping to find the answer as to what I am missing without having the user to click the refresh button.

[This message has been edited by George (edited December 31, 2000).]