I have all these tech centers mainly because I'm farming for X-Ranks, which are absurdly rare (in comparison, Aries has double the drop rate) and randomly chooses what unit to rank up. I'm trying to have all of my X-Ranks go into my rare units, so these tech centers help speed up the process. Of course, I could also destroy every unit that I don't want ranked up to ensure that these X-Ranks go where I want. However, tech centers generate a lot of gold for me, and I generally don't like having to go into the trouble of rebuilding my base again.
Have you tried grinding insane tesire? pretty sure x-ranks are common there.
I actually started farming normal Sector XIII instead of Insane Enson for X-Ranks due to the game engine changes (my average kills in Enson went down to around 600 from 1200+), and then all of a sudden rares and X-Ranks were dropping like candy. Since the update, 6 X-Ranks have dropped for me (sadly two of those I couldn't get as the boss dropped it and and then the level summary popped a second later). Either I got lucky, the drop rates changed with the update, or you're on to something with these later levels dropping more rares. :D
Last Edit: Aug 27, 2018 20:53:57 GMT by Tranquility: Meant Sector XIII, not Section VIII.