If you already have RankTracker from SEOPowersuite then you don't really need any other software.
Just ensure that your set-up is correct, it should display the same results you would manually going through.
Just go to Project Preferences > Preferred Search Engines and set yours accordingly.
Instead of researching new software, look at the tools you already have. If a result is inconsistent open a fresh incognito window, be sure to set the correct Google local and check which one is accurate.
RankTracker is more than powerful enough for tracking SERPs since if you know it well enough you can create a workspace that gives you as much information as possible in an easily digestible format.
If you are looking for a change, the others above have listed out the alternatives but if you already *have* the software why make another financial investment?