It can be done,you would roll a highside or lowside.But I may have seen that done once if any.We,like you try to bank the same with the same.Although there was a time we banked 3 19.9 transformers.277/480.Two had two highside bushings and one had three.Took a bit to figure all that out but we did.That was years ago and by now I forgot all the details involved.....I just wanted to ask if anyone checks voltage on changed-out transformers before hooking up the secondaries,its a pain but Ive seen that done here.