I mean the Saka Heavy Hoplites. Why are they using the old classic phalanx and do not fight in the reformed style (successor or iphilcrates) ? If the Sakas conquer the Bactrian lands and install the allied government, they should be able to recruit units similar to Bactrian. But it seems that Greco-Bactrians do not have any classical hoplites, they use the hellenistic style units like pezhetairoi. In fact, it seems that the nearest hoplites fighting in classical overhand style are far away on the coast of Asia Micra.

Also, can anyone give me some historical backup on these heavy hoplites?

Looking forward to your answers!