Well, I think I answered this last time you asked, but if not, here's what I think it probably going on. I think your tree is elongating (etiolated) due to not receiving enough light. Especially if your tree is 100% indoors. Citrus really do need a lot of sunlight - indoors 100% of the time is just not going to give a citrus tree enough light to prevent etiolation. So, you're going to constantly see this stretching of the branches in an effort to try to reach sunlight. If you want a bushier tree, I would provide it with more additional light. I see you're already trying to do that, and that is great, but I think it's a light issue, and pruning those longer branches may not achieve the look you're after if your tree continues to eitiolate.

Patty S.