as Slasher said, it's about the commitment : Fed will not play Tokyo or Beijing, which means that he will have only played 2 ATP500 tournaments in the calendar and will not be able to fulfill the comitment to playing 4 ATP500 tournaments in the calendar year.
Which means that he will get a zero for Tokyo/Beijing, just like last year.
Actually, in order for him to get an extra zero, he must also skip Basel/Valencia. If he plays there, he will get 3 ATP 500 this year, and Halle stays. Only by missing 2 ATP 500, he takes his Halle out.