I'm assuming you have a wideband, not a narrowband, so I will leave that up to you to confirm.
I'm not familiar with your setup, but a wideband air/fuel ratio meter is commonly used in modified or performance vehicles where the stock narrowband sensor may not provide enough accuracy or resolution. The wideband allows for a more precise measurement of the air/fuel ratio across a broader range, typically from lean to rich mixtures. This information is useful for tuning aftermarket engine management systems, optimizing performance modifications, or monitoring the engine's health. The bouncing you mentioned in your first post is expected, provided you are at part throttle cruise. This information is an average air/fuel ratio taken from that bank. For a V8 engine, you should have a wideband for the other bank because it's important to know what the other half of the engine is also doing.
I just noticed you stated this was an impulse buy, and that's fine; your car, your money, do whatever you like.
Good luck
Michael Plummer