Won't hurt to do the 2D ulrasound as long as you are comfortable with it but, just keep in mind that no Dr. can tell exactly how big a baby is going to be. All they can do is measure & guess. My daughter was told that her baby would weigh over 10 pounds & she had to have a csection. When the baby was born he weighed 7 lbs. What a surprise. As long as you know about when the baby is due & the baby is gaining & thriving there shouldn't be any problems. The baby being active is a good thing! Enjoy your pregnancy!
Don't know what you mean about the baby's blood. But I'd say that 942 is probably close enough to1000 not to be unduely concerned.
Ultrasound is an inaccurate science and the weight estimates can be off.
I have had 1 dr tell me baby was big and another tell me baby was small, all within the space of 2 days. The reality is really probably somewhere in between.
If baby is very active it is probably just fine.
Don't be pushed into any investigations you are not comfortable with.