[modeless]

Thanks! It's plausible that you might not see predicted satellites and very plausible that you would see extra ones. Predicting satellite visibility is very difficult because it depends on unknown factors like the shape and BDRF and precise orientation of each satellite. My site necessarily uses a simplified model, which will sometimes be wrong in both directions. There will be many visible satellites in the sky that aren't shown on the site, and some that are shown on the site may end up not being visible after all.

For a guarantee of visibility look for satellites marked "bright" in the UI (which will usually be ISS or Tiangong). For a more comprehensive catalog of satellites that may or may not be visible, check out sites like https://www.heavens-above.com/.