We use it for our Change Management process. Change requests can be started as you bid them out. You can update the contract (Price) and update the estimate (Cost - JC) or you can do an internal that only updates job cost and doesn't hit the contract with the owner/GC.

You should tag Purchase Order and Subcontracts on the change request. Then, when you write the Subcontract Change Owner, you can attach the change requests that apply to them. We have a policy of not writing a change order to a sub without having a change request, so we don't write change orders to subs that aren't covered in job cost.

Once they are finalized, you can submit them to your owner/GC for approval. Then when you pull together an Owner Change Order, you have already approved Change Requests added. But that process depends on how your owners/GC's work and the type of work you do. 

The system can be set up to allow PM's to start all of these processes but they can't hit the contract or job cost without accounting approval. Or they can fully approve everything and update job cost and the contract when they are ready, depending on how your company works. 

It helps our PM's to be on top of their job cost and contracts with the owner and the subs.

We use Procore for RFI's, Submittals, Drawings, etc. But, all of these can be input and tracked in Project Management. The process is much better than Excel but not as good as Procore. When Project Management came out, we were doing everything in Excel, and implementing it helped streamline our PM's processes and gave everyone insight into what was happening on the job. Much easier for someone else to step in and help out if needed.

Hope this helps!