I flew back to the U.S. on Thursday, arriving at DFW as my first port of call. There was a long line for customs (post baggage claim) and the agents were scrutinizing everyone's form very closely.

I noted that my purchases outside the U.S. totaled $10, but did not list the purchase (a small stuffed camel) on the back of the form. My understanding is that as long as you are below the limit on which duty is imposed, there is no need to list your purchases. The agent looking over my form asked me what I purchased (no big deal) and then told me that I needed to note it on the back of the form. I responded that I thought that was only if you exceed the free limit and she said, you must do it for all purchases.

I've entered the U.S. dozens of times, always with purchases well under the duty threshold, have never itemized and have never once been told that I needed to by any customs agent.

Have I been doing it wrong all this time?

Thanks!