Fetal movement

Samantha • My husband and I are proud parents of two beautiful children, our daughter is 5 and our son is 3 now we are expecting twins due October 11th!
So I had an appointment today and my ob wants me to start documenting their movement. He said they should move 10 times in a 2 hr span. Is that 10x combined or 10 a piece? I feel baby B more than Baby A im concerned she wont meet the 10x in a 2 hr span.