The current Invigorator/ProAnimator renderer outputs in 8-bit (even though everything internal is done in floating point).
You may see banding in certain circumstances (when the color variation across a large portion of the screen is minimal),
but most users won't see any.
Now that After Effects supports floating bit output, we're looking into higher-bit output.
Stay tuned. And let us know if you have any other questions.
And, as always, feel free to download a demo of the product to see if it does what you want.