Procurement says their Purchase Order is the Ten Commandments and nothing will vary it. Yet, you know or suspect there are other agreements that can vary it.
Get thee to the business person who champions your deal. Ask them if you really must start with a purchase order. If so, ask if there is a master agreement that can override the terms of the purchase order , e.g. a clause that states that in the event of a conflict between the master agreement and the P.O,, the Master Agreement controls. And make sure that Master Agreement provides the protection you need.
Installation of a computer networking system integrating offices around the world is not like selling cocoa beans fresh from the boat. You have to take this out of the realm of a commodity contract.
What if you can’t get off the dock and feel like you are trading cocoa bean commodities? Your interpreter, i.e. your business contact at the buyer, is of no help? Round 3, in the next post, is the knockout round.