Correct. The Optimize Face command warns you that parameters will be lost. It's good practice to use Optimize Face as the initial command when importing geometry from 3rd party products to clean up redundancies. With the advent of Synchronous Modeling, removing parameters from a part does not raise the concerns that it used to. As these were NX8 parts, you may also have found that a feature playback corrected the issue. Something to consider in the future.