Abstract: The need for more and more dependable systems has been increased in the last decades. Strategic decisions during the design of these dependable systems require the joint control of the estimated cost and the product quality. Cost efficiency and development time became the most important factors of the software development process according to the international trends. The estimation of the cost remains a difficult problem till yet, despite of the use of standard, easy to understand modelling languages. On the other hand, no working environment is known supporting the gradually refined cost estimation derived automatically from the formal product models. In this paper the experiments of a pseudo cost estimation are detailed with a special emphasis on the cost estimation driven system design.