I’m sorry, I said it in an unclear fashion.
Under the project settings, you can set the project to “start numbering frames at” any arbitrary number. The default is to start numbering frames at 0, so in a 30-frame timeline the frames would be numbered 0-29.
I considered the possibility that FCP looked at the last frame of the footage (29, in this example) and mistook it for the duration of the footage. What I was saying is that I’m setting the project settings to start numbering at 1, so that a 30-frame timeline is numbered 1-30.