In the business we run (events) it can happen that the amount the initially agreed with the client will be changed due to the actual consumption in the vent it self.
This in turn means that the deal amount might be modified even after the deal was closed won.
Do you have any experience/suggestions of how to manage such a use case, especially in regards to setting a process to ensure that all deal amount are finalised.
I was considering to add another stage after closed Won called Amount finalised which might be a better user experience for the sales team to differenciate between deals that the amount is yet to be finalised and the ones that amount is already finalised compared to adding a new property to the deal.
Interestingly enough, we have a similar idea. We have a flexible contract process with pricing guidelines that are often contingent on what a final product finally turns out to be, meaning that the amount under consideration for billing purposes really isn't know until the last moment.
What we are planning to do is to set a barrier to moving the deal to closed-won until the contract has actually been signed by all parties (and prices finalised), using a workflow to trigger questions that have to be answered by the salesmanager (kind of a checklist) before the deal can finally be moved to closed-won.
We're still working on this, but it's the approach we're going to be taking, as it then means we can communicate a finalised contract to an ERP/finance for billing purposes.
Your idea of compulsory properties is a good one, it's basically what we are going to use to hinder the move from one stage to the next: that way someone can try to make the move, but will be pushed back until everything is done.
Basically we will be setting up a contract template as a custom object that will be generated at the creation of the deal. Each movement from one stage of the pipeline to the next triggers the next stage in the process and requires updates before it can be moved.
Using a workflow also lets us get the process laid out clearly, as we are a regulated company (rating agency) and we have to document these things for our compliance people, who are lawyers and not programmers. HubSpot's workflows are self-documenting and are fairly easy to understand for non-programmers!