Only special subsets of the unit interval are considered, the restrictions are of finite nature, causing that the computation power of this paradigm fits into the framework of Church-Turing thesis: unlike real computation, interval-valued computation is not capable of hypercomputation, is not corresponding to an unrestricted ideal analog computer.
Such a model of computation is capable of solving NP-complete problems like tripartite matching. “The validity problem of quantified propositional formulae is decidable by a linear interval-valued computation. As a consequence, all polynomial space problems are decidable by a polynomial interval-valued computation. Furthermore, it is proven that PSPACE coincides with the class of languages which are decidable by a restricted polynomial interval-valued computation” (links added).