Histograms of the PL slope α in the hybrid (LN plus PL) PDFs that match four different SF models (black, blue, red, and dashed red) to the ϵ_ff measured in PHANGS. The fiducial shortened-duration broad-PL MFF model is shown in black, the full-duration broad-PL MFF model is shown in blue, the Burkhart smooth-PDF MFF model is shown in red, and the Burkhart smooth-PDF SFF model is shown in red with a dashed line.