I'm having issues configuring a exclusive gateway with my process. There are three variables at play, a PO number, Contract Number, and Amount with two possible routes to take. I'll outline what routes I want and what I've come up with, but it isn't routing correctly and gives my process errors. 

Route A: 

When Amount < 500 OR when Amount is >= 500 plus either the PO or Contract number is filled. Aka if the amount is over 500 a PO or Contract number is required to move in this direction (but never both). 

Route B:

When Amount >=500 and both the PO and Contract numbers are left blank. 

Everything should be routed to one of these two options based on the three variables. 

This is how I configured it in the gateway, but it isn't working. Any suggestions? 

Route A: 

(number(/dataset/Amount)<500) or (number(/dataset/Amount)>=500 and ((/dataset/PO_Number!="") or (/dataset/Contract_Number!="")) 

Route B: 

(number(/dataset/Amount)>=500) and ((/dataset/PO_Number="") or (/dataset/Contract_Number=""))