Large values of error terms of a class of arithmetical functions

We consider the error terms of a class of arithmetical functions whose Dirichlet series satisfy a functional equation with multiple gamma factors. Our aim is to establish Omega(+/-) results to a subclass of these arithmetical functions with a good localization of the occurrence of the extreme values. As applications, we improve the Omega(+/-) results of some special 3-dimensional ellipsoids of other writers and extend our result to other ellipsoids.