Invoice charts
Counts and sums come from the search index (SearchInvoiceNodesAsync with aggregations); one measure per aggregation entry.
Invoices by status
Total amount by status
Sum of TotalAmount per status, across currencies
Invoices by currency
Invoices by customer type
IssuedTo → Customer.CustomerType
Invoices by customer country
IssuedTo → Customer.BillingAddress.CountryCode
Invoices by work type charged
ChargesFor → WorkOrder.WorkType