In order for companies to improve the maturity level of their development process, they need to design new methods or adapt the existing ones. This research aims to deliver a proof of concept of how incremental method engineering supports the maturation of methods in a product software company. We show how the adaptation of a method can lead to a higher maturity level. We assessed the method of a case company by means of the situational assessment method, resulting into the maturity level and situational factors. We also modeled eight different prioritization methods according to their maturity level and situational factors to find out which of these could be implemented into the case company’s method in order to evolve to a higher maturity level. After matching the situational factors of the available methods with the company factors we find one method that is suitable to implement into the existing method at the case company. We explain how the implementation can take place and how this would evolve the method to full maturity.