In this paper we investigate the effect of the heuristic IR constraints on IR term-document scoring functions within the recently proposed function discovery framework. In the earlier study the constraints were empiricaly validated as a whole. Moreover, only the group of form constraints was utilized and the other prominent group, the adjustment constraints, was not considered. In this work we will investigate all the constraints individually and study them with two different term frequency normalization, namely normalization scheme used in DFR models and relative term count normalization used in language models.