It is really hard to discuss your point. There are some possibilities. One is that we don't know exactly what you are looking for, what your track is and what you expect from it to sound like, another is that you just didn't found proper settings for your purposes. Last is that the StereoPack is simply not capable of doing a good job for you.
If proper setting is what is missed you should at first consider whether you are trying to add some ambience to a mono track or enhance a stereo track. In the first case you should use the PseudoStereo as insert if your application automatically switch the mono track to stereo and as a send/return in oposite.
For stereo track you should use the StereoEnhancer and try all three modes to be sure that it will do best for your track.
Then you can spend some time to get the best sound of it and very delicate enhancement gives the best results.
Regards,
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Mateusz Wozniak
PSPaudioware.com