OCI has separate VM capacity marts, and Storage Capacity and Chargeback marts for different use cases.
As a rough rule of thumb, most OCI users tend to build multiple queries / reports to tackle both Vmware chargeback and storage chargeback.
Storage chargeback - you may want to annotate your VMware storage with application "VMware", and exclude capacity going to application "VMware" in your storage chargeback reporting
VM chargeback - report vm capacity by application, and tier, etc.
I have a US .gov customer doing something similar - rather than consume reports, we have a few different SQL queries running weekly to extract specific data sets that populate a billing system they built - their chargeback model includes other data feeds that OCI will never gather.
Usually customers using OCI for chargeback will have custom reporting requirements - these customers may find our canned reports interesting for idea generation, but often the reports themselves are built as part of a consulting exercise to obtain requirements.
We have some customers whose chargeback models vary from OCI's model, and in those environments we work with the customer to drive how their objectives can be met - I can think of a bank that prorates chargeback across all the applications that sit on a host's capacity. The same bank wants DR hosts' applications to be charged back for capacity, not the primary hosts' applications (in normal OCI chargeback, if a host has a LUN that has a remote replica (SRDF, mirrorview, Truecopy, etc), the remote lun's capacity will be charged back along with the primary lun's capacity to the source host on the principle of the source application is responsible for the replicas and should pay accordingly.