How does “Four views of the same figures” work on the Aged Receivables page?

Summary is the flat list — one line per customer per organisation, grouped by organisation or by customer when you want subtotals. By Company puts each of the group's organisations in its own section with the customers under it; By Customer puts each customer in a section with the organisations that bill them under it, which is the group's true exposure to one party; By Project sections by tracking option, each line naming the organisation that billed it. The grand total is the same in all four. Where: Aged Receivables (/accounts/sales/aged-receivables).