Changes made by Regulation (EEC) No 1579/74 of the Commission of 24 June 1974 on the procedure for calculating the import levy on products processed from cereals and from rice and for the advance fixing of this levy for these products and for compound feedingstuffs manufactured from cereals: Regulation (EEC) No 1080/68 of the Commission of 26 July 1968 on the procedure for calculating the levy on products processed from cereals and from rice and for the advance fixing of the levy for some of these products