The Tempest VS waves sound different from the Evolver VS waves

While the Evolver uses wavetables, the Tempest uses samples of the wavetables so they're not exact duplicates. You'll notice some tonal differences between the VS samples and VS wavetables because of this, and what you are hearing is normal and part of the voice architecture for the Tempest. Within the context of a mix it shouldn't be too noticeable.