Can I top up my transportation card at T3 Beijing capital airport express counter.

I am planning to visit with my wife and three kids in near future. My question is that can I get 5 yikatongs of value 70 rmb each (20 rmb deposit+ 50 rmb top up) at T3, capital airport at the airport train express counter right away? Or can I get 5 yikatong with a deposit of 20 rmb only from the counter and look somewhere else to use an unfamiliar machine to top up additional 50 rmb bal?