So, I recently got "talked to" for not declaring 4 laptops I was carrying back for a non-profit (from an overseas convention). I was told they were commercial goods and I should have declared them. This begs the question of what constitutes "commercial goods"? If you have one company laptop does that constitute "commercial goods"? Do presentations? I had always assumed it only referred to samples or things for sale but according to at least one agent I am wrong.
If they are not your personal goods for personal use and are instead owned by a corporate or business entity of any sort and being
imported for sale/distribution, they are more likely to be commercial goods. That is probably why you encountered what you did.