Ultrasound today !! Question about 9 weeks & almost identical heart rates!

Emily
I had an ultrasound today to check up on babies due to stabbing pain I've had around my belly button. 
Baby A's heart rate was 173 & Baby B's heart rate was 171. This question is to identical moms and fraternal moms. Around 9 weeks 1 day,, were your identical twins within a few heart beats or if you had fraternal did they have close heart beats or varying? 
Thankyou!!!