I use to have an almost 11 footer once in my living room. I had cut back some dried tip off a couple of the branches and they never grew back as straight as they were before they were cut since the new growth grew off to side from where they were cut, so they looked a little funny.
Also, if you ever try to root a branch tip, it will keep growing
like a branch, not an upright tree
and the very top of the tree
is almost near impossible to root, even under the best conditions!
Because my tree
was so tall, it was very close to touching the ceiling, I HAD to cut it back.
I cut it back maybe 8" and I knew I would get those multiple tips from doing so, so that's why it's not recommended, it's said cutting the top back ruins the Symmetry of the tree
, well, I didn't think it did at all, if fact, I thought it looked rather nice! Gave it a more fuller looking top.
So, if you don't mind more than one top/tip, cut away, but I would wait until spring