Number of clouds in the spiral arms (N_{cloud, SA}) as a percentage of the total number of clouds (N_{cloud, tot}) in the complete distance-limited sample (left panel), and the integrated cloud mass within spiral arms (M_{mol, SA}) over integrated cloud mass within the inter-arm region (M_{mol, IA}; middle panel) versus different velocity offsets with respect to the spiral arm model ridge line. In the panels, the red diamonds show the values for our chosen velocity offset ΔV = 10 km s⁻¹. Also shown is the KS test p−value (p_val, right panel) variation with respect to ΔV calculated from the property distributions of the clouds in the spiral arms and inter-arm region. Considered properties are effective radius R_eff, velocity dispersion σ_v, molecular gas mass M_mol, molecular gas mass surface density Σ_mol, virial parameter α_vir, and aspect ratio AR. The dashed line indicates p−value = 0.05.