Steve measures a spring's stiffness $k$ dynamically. He hangs a precisely known mass $m$ from the spring and times its oscillation period $T$ with a stopwatch whose absolute uncertainty $\delta T$ is independent of the duration timed. He then computes $k = 4\pi^2 m / T^2$, obtaining uncertainty $\delta k_S$. Tiffany measures the same spring with the same stopwatch but uses a mass nine times larger. What is her uncertainty $\delta k_T$ in terms of $\delta k_S$?