HCG beta twins or Singleton?

Chelsea

My first beta 9dp5dt was 490, second beta 11dp5dt 813.75. Anyone have a guess if it’s twins or a singleton? My gut tells me it’s twins but I didn’t quite double at the 48 hour mark.m

We transferred one 5AA spontaneously hatching blastocyst and one 4AA blastocyst. Triple stripe pattern and uterine lining 8.