The name of the qsp has also an impact on where the saves will be stored. Means if you have an SOAv024.qsp and then switch to - lets say -- updated version named SOAv030.qsp then even thou it is same from variables perspective (maybe e.g. some bugs fixed?) it might happen that your game won't find the "old XYZ saves" anymore and will show as if you haven't played nor saved the game at all.
And in general all the machine translations done by different authors, different approaches, different vocabularies (especially for the variables), different scripts are not cross-compatible for savegames.... Sometimes even the authors themselves do some major overhauls to their scripts thus making old saves invalid (good example is SoB in version 0.30 where the author has cleaned up his coding making old saves obsolete).
Hope my explanation has brought some light to the problems of QSP engine (and engine alone.... from a technical point of view it could be solved with some slight modifications to QSP engine, e.g. by forcing the correct additional technical enumeration to variables, or if the authors would script it with the translations in mind, but I think this is a different story... )