As Fig. 6, but showing the ¹³CO (left) and C¹⁸O (right) J = 3− 2 fluxes for all models. Colors indicate different α_visc. Models with and without CO conversion through grain-surface chemistry are shown with solid and dashed lines, respectively. The age range for disks in Lupus is highlighted in red. Few models show a significant decrease in ¹³CO line fluxes, except for models with α_visc = 10⁻² that have low disk masses. The C¹⁸O line fluxes do show a decrease with age, especially at later disk ages.