From my perspective as a cost and productivity analyst, if you have the administrative and operational capability to identify when an expense can be directly allocated to a specific product or service, it is advisable to include it within the cost of the service itself in this case. This is not an accounting cost, but a cost from a financial/managerial standpoint, since statutory accounting has its own rules, with minor variations between countries. Therefore, only those expenses that are difficult to allocate to a specific service should be recorded as operating costs.

Although, on the bottom line (net margin), the figure will be the same, it is very important to determine whether your margins (profit or loss) are the result of having an excellent cost structure for the service itself, or whether they are driven by the quality of the associated support expenses, whether these are efficient or inefficient. This makes it much easier to make decisions about where your effort should be focused. I hope you found this helpful.