Is it there any problem on getting two transit Visa in same month ?

I mean staying in China for 3 days then leaving and after two weeks coming back for three more days and then leave back again? Of course with all tickets already booked and a residence confirmed in Shanghai ?
I did this type I have already done it in same airport same moment when I got there. It was completely free of charge and they did it very fast in Pudong Airport at the registration transit cue. But now I need to do it twice in same month and I don't know if that is possible.