Performers convey musical meaning not only through pitch and dynamics but also through micro-timing deviations. This study examines performance analysis and timing in Georg Philipp Telemann's 12 Fantasias for Solo Flute, focusing on how musical elements, such as implied polyphony, onset positions, and meter, influence musical performance. We release a corpus with annotations on interleaved voices gathering 11 musicological sources. We first evaluated how simple rules may detect such interleaved voices from the scores. We then analyzed six complete recordings of the fantasias, comparing their timing deviations against a metronomic interpretation. Results show significant timing deviations influenced not only by note position within rhythmic groupings, but also by the presence of interleaved melodic voices.