I thought I would include my photo of this 90 degree fitting placement. I should note that I scanned the forum for topics like this prior to my post (there are many "offset p-trap" issues that seem to come up), but I wanted to ask the same type of question as it regards to the plumbing code. In my case, I would keep the one 90, and possibly put the trap right after. You can see the brass 90 snug up against the joist under the red shower pan. They had a galvanized leg coming off that to grab lead pipe to the old drum trap. OR - I could put maybe a foot of galvanized back in before the trap to get past the next joist (greatly increasing the amount of skanky water in retention.)
Thanks again, sorry for forgetting photo on first post.