I agree with you, also the book I mentioned places the beads in a later time period than Franchini. the link is to the Picard page showing various examples of the same (picture is of one of the beads in the link). Also there are several examples pictured on the inside cover of the Picard book:
"Volume VI, Millefiori Beads, 88 pages with 68 full color plates featuring over 3000 Venetian beads traded in Africa,Introduction on the history of millefiori work by Jamey D. Allen"