Anybody else have a correlation between twins and hCG?

I know they say it is an unreliable way to tell, but I had some abdominal pain (which is how I found out I am pregnant following a miscarriage in July, twins) and they’ve kept me in the hospital for monitoring a possible ectopic pregnant. I won’t know until later on when they do my 5th ultrasound so far when I return for my follow up.

Anyways my beta levels are:

Thursday - 55

Friday - 175

Sunday - 375

Monday- 653

What do you guys think? The Thursday/Friday were exactly 23 hrs apart and Sunday/Monday were 24 hrs apart.

So excited to have it grow so fast! But I thought doubling was every 48-36 hrs in early pregnancy.

How far along do you think I am?