No matter that, you will end up with an odd amount in account A. It helps to draw a chart
Assuming your goal is 90K in each account:
1) transfer 50k each from A to B,C,D, you will left with 50K in A, and 100K each in B,C,D
2) transfer 10K each from B,C,D back to A, you will left with 90K each in B,C,D and 110K in A (50k from step 1 plus 20K each from the transfer from B,C,D)
So Now you have 4 tickets to Asia/Europe total plus addl 20K in account A.