Histogram of maximum variation, |Δm|, from 100 simulated DRW light curves of an M_BH = 4 × 10⁷ M_⊙ black hole, sampled at the rest-frame effective times of our combined observations of all three images of A2744-QSO1 as is shown in Fig. 3. Rest-frame UV (F115W) variations are shown in light blue and optical variations (F356W) are shown in dark blue. We chose to show the F356W band here because it has the most epochs (see Table A.1) and therefore has the highest probability of detecting a significant event. The gray-shaded area represents variations that are below the typical errors of 0.3 magnitudes (including systematics) in our photometry measurements in both bands. Even with the sampling of our full light curve, the probability of detecting a significant variation event (|Δm|> 0.5 magnitudes) is relatively low.