The most common problem that can occur is reporting the vertex count based on subdivision smoothing applied to the model instead of the actual base mesh. It’s easy to forget if you have subdivision smoothing on for the various elements of your model, but you should turn it off for all parts of your model before you gather up the vertex count information.
Finally, if you have a model that consists of multiple elements (e.g. a car with separate wheels), make sure you select all of the parts and not just the main body or biggest element when reporting the vertex count.