90 degree drain turn?

Please forgive what is probably a very simplistic newbie question.
Current tub drain (1.5" id pvc) has two 45 degree elbows - causing it to require an angled hole through the floor joist.
Am looking at moving the tub - which will mean rerouting the drain and replacing or sistering the joists.
QUESTION -
Is it legal/accetable/wise to turn this drain horizontally at 90 degrees rather than 45?
My purpose would be to allow me to bore a straight hole through the joist rather than an angled one - and to make that hole closer to the end of the joist (I'm already within the end third - but this would take it further in)
This would definitely be easier to cut - and (I'm assuming) be less weakening
to the joist.

If there is a problem with my plan or the logic behind it - please let me know.
Thanks

(not a pro)
I totally agree with your logic on the structural integrity of the joist. It's probably an issue of how drastic a 90deg turn would be. Can you make a long sweep instead of using an el?

yes - there should be plenty of room for a long sweep.