Country differences in response styles (RS) may jeopardize cross-country comparability of Likert-type scales. When adjusting for rather than investigating RS is the primary goal, it seems advantageous to impose minimal assumptions on RS structures and leverage information from multiple scales for RS measurement. Using PISA 2015 background questionnaire data, we investigate such an adjustment procedure and explore its impact on cross-country comparisons in contrast to customary analyses and RS adjustments that (a) leave RS unconsidered, (b) incorporate stronger assumptions on RS structure, and/or (c) only use some selected scales for RS measurement. Our findings suggest that not only the decision as to whether to adjust for RS but also how to adjust may heavily impact cross-country comparisons. This concerns both the assumptions on RS structures and the scales employed for RS measurement. Implications for RS adjustments in cross-country comparisons are derived, strongly advocating for taking model uncertainty into account.