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Desvousges et al. (2016), in their reply to Chapman et al. (2016) in this journal, reference the empirical adding-up test in Desvousges et al. (2015). Desvousges et al. (2015) find that their contingent valuation method (CVM) survey data does not pass the adding-up test using a conservative, nonparametric estimate of mean willingness-to-pay. In this comment I show theoretically that the survey fielded by Desvousges et al. (2015) is missing important features necessary for the conduct of an adding-up test. Next, I describe how the CVM data collected by Desvousges et al. (2015) suffers from non-monotonicity, flat bid curve and fat tails problems, each of which will cause willingness-to-pay estimates and standard errors to be sensitive to the approach chosen to measure the central tendency. Using additional parametric approaches that are standard in the CVM literature, I find that willingness-to-pay for the whole is not statistically different from the sum of the parts in two of three additional estimates. In other words, the data passes the adding-up test. The negative result in Desvousges et al. (2015) is not robust to these alternative approaches to willingness-to-pay estimation. The primary reason is low data quality.