My experience was based mainly from when Los Alamitos offered the twin tri back in 1992, here is a link to an L.A. times article from back then,
http://articles.latimes.com/1992-02-...ecta-carryover
plus our local dog track in Idaho offered a twin quin and twin tri and tri-super that had split payouts. So like I said it is a different world now but that is what I remember.