it depends on the esther of Tren that dictates the injection frequency. Theres Tren Acetate which is the short esther Trenbolone, and then theres Tren Enanthate which is long esther tren. THeres also Tren hexahydrobenzyl (sp?) which is close to the same esther size as acetate (3 days or so i believe) and known as Parabolin.
As for your tren, i believe its Tren Acetate, hence the EOD or ED injections. If you want less injections, go with Tren Enanthate.