So you use 1000 XTS-9 for 5 injectors. That's a pretty steep price. But I think a blueprint instead (retroactive for ppl that finished this already) for the same building (XTS-10 Injector, limit 1/planet, etc) with a requirement like 5-10 XTS-9 to build actually gives life to the old XTS-9 repeatable mission. Hey, it was done with Sulcation Portal/tech parts.