The nurse just called.
My beta is 892 (!) and my progesterone is 29.3. The doctor was excited about the progesterone (as I am an old fart and could have issues). I am floored by Hcg number!!
I know yesterday was 18 dpo. The average number for Hcg is 292 with a range of from 70-758.
Are you thinking what I'm thinking!? No, you are RIGHT! You cannot tell twins from Beta/HCG because the average/range of twins falls within the average/range of singletons. What I really want is that the number doubles by tomorrow. That would be very good!
[ETA] Here is a database in which women enter in their beta numbers on dpo. It's called Beta Base.
What do you think!?