Number of preconditioner steps in ISTLBackends

First of all this is a very minor issue but I wanted to report anyway. I realized that our ISTLBackends use 3 preconditioner iterations. This 3 is hardcoded, see for example ISTLBackend_SEQ_Base:

        Preconditioner<Native<M>,
                       Native<V>,
                       Native<W>,
                       1> prec(native(A), 3, 1.0);

Is there a reason for doing 3 preconditioner steps? Isn't one sufficient? Should it be possible to change this as a user? I would opt for making it accesible to the user and using 1 preconditioner iteration as default (unless there are numerical reasons against that).