The Deliberative Reason Index (DRI) is increasingly used to assess the coherence between considerations and preferences in deliberative settings, including applications to LLM-generated data. Under low-signal conditions, however, the standard DRI can produce inflated scores by treating near-zero correlations as evidence of consistency. Monte Carlo simulations across common study designs show that this bias increases with group size and yields positive values even under random response. A modified DRI is introduced that applies a continuous penalty to low-signal correlation pairs. The modification preserves the original scale and reduces exactly to the standard DRI when substantive signal is present. A threshold sensitivity analysis identifies {\tau}=0.2as the optimal parameter. An empirical check with archival deliberative data shows that substantive inferences remain unchanged. The modification improves the reliability and comparability of the DRI in low-signal settings.