The world’s economy has been significantly affected by the ongoing pandemic crisis. Its logical reflection is a deteriorating condition of national and regional economies and their vehicles—enterprises. Negative effects of the crisis have influenced both the manufacturing sector and the services sector, where some segments have been hit fatally. In the corporate sphere in general, including in the services sector, there has been a growing need to change the approach to corporate strategy. The strategy should be generated based on management of value-creating processes with the objective to maximize satisfaction of customers while minimizing costs. This is also the topic of this paper. A representative sample of small and medium enterprises from the services sector have been surveyed about their size, using mathematical statistics and models that have been proposed to maximize profit probability. The objective was to propose models that maximize probability of profit and, at the same time, minimize costs for each combination of value chain activities (input logistics, provision of services, output logistics, marketing and sale, servicing, and other accompanying activities, purchasing material management, science-technical development, human resources management and company infrastructure). The main outcome of this paper is the fact that we have been able to prove the functionality of the tested model, which has demonstrated the growing importance of value stream management in relation to the size of enterprises. Such a universal and structured model provides a practical tool for the definition of economic-financial, investment and personnel policies in enterprises.