If there are no tracks in the project, and you import a tick-based audio file to the Clips List, Track List, or empty space in the Edit window, you are prompted to either import the tempo from the file or use the default project tempo. To keep the default project tempo, and have the loop conform to the project tempo, click Don’t Import.

If the project already contains at least one track (regardless of track type), you are not prompted to import the tempo from the file and the file is conformed to the project tempo.