A new Open Source Strategy applies a concept of equal treatment:
The Commission will ensure a level playing field to open source software when procuring new software solutions. This means that open source solutions and proprietary solutions will be assessed on an equal basis, being both evaluated on the basis of total cost of ownership, including exit costs.
What is apparently the advantage of Open Source software is that you get the source code disclosed and enjoy the rights to build upon it. The argument of total costs of ownership is completely unrelated and does not even consider the advantages of the mentioned openness characteristics.
A decision based on “total costs of ownership” actually implies that the Commission does not care at all to promote Open Source. It is like billing wine and water equally per litre. Total costs of ownership calculations are usually rigged and thus promoted by the commercial adversaries of open source that want to preserve their business model.