definiens: means the gross amourit invoiced by a member of the HOECHST Group or its Affiliate or sublicensee for arm's - length sales to a Third Party of HOECHST Group Products or HMRl Products after deducting normal and customary trade discounts actually allowed or taken including Prime Vendor and Medicaid rebates and profit drawback taxes such as are imposed in the United Kingdom, returns, credits, customs duties, or taxes the legal incidence of which is on the purchaser an, d separately shown on the member of the HOECHST Group 's or its Affiliate 's or sublicensee 's invoices and transportation, insurance and postage charges, if prepaid by the member of the HOECHST Group or its Affiliate or sublicensee and billed on the member of the HOECHST Group 's or its AfIiliate 's or sublicensee 's invoices as a sepaiate item