I can see NHS suing PXYN for payment, it could go something like this...
NHS: Your Honor, PXYN owes us $120M and won't pay us.
Judge: When was this money due.
NHS: Well, our agreemernt never actually said when they had to pay us.
Judge: Why not? Did you forget to include something?
HNS: No, we had a payment schedule, but we decided to remove it.
Judge: Oh, you replaced it?
NHS: No, not exactly. We removed the payment schedule and didn't replace it with anything.
Judge: Why didn't you replace it?
NHS: Maybe that's a question better ask of PXYN.
Jugde: PXYN, why didn't you replace the payment schedule that was removed?
PXYN: On the advice of counsel we decline to answer that question on the grounds that it may incriminate us.