IRecursiveElementProcessor usage

In order to analyse method calls in my R# plugin, I create a StageProcess that implements both IDaemonStageProcess and IRecursiveElementProcessor.

Implementation looks like this:

        public bool InteriorShouldBeProcessed(IElement element) { return true; }

        public void ProcessAfterInterior(IElement element) { }

        public void ProcessBeforeInterior(IElement element)
        {
            var checker = ...

            if (checker.IsInvocationAllowed) return;

            //else add highlighting
        }


Now a few questions:

1. Is that the recommended approach?
   
2. How should one decide whether to put such analysis in the "ProcessBefore" or "ProcessAfter"?
3. Is it correct to simply return "true" from InteriorShouldBeProcessed?

Thanks,
Andrew