You're pretty much correct.

If the scale says >32kg, the agent is generally required to charge an additional fee. And indeed, at most airports, airlines pay different handling fees depending on whether the bag is regular weight ( < 23kg), between 23kg and 32kg or overweight ( > 32kg). At many airports you'll also notice that any suitcase >23kg will received a "heavy" sticker.

With regards to size, I believe the general policy is to "measure it if it seems oversized". Hence, agents have more latitude and many won't care about an extra inch or two.