Top: unsigned surface flux from 3D simulations of a single active region, using the KD3 diffusion profile (orange), quenching profile (purple) and MLT profile (yellow). The equivalent 2D SFT flux is shown in the dotted blue (without decay) and black (with decay) curves. Bottom: northern polar flux (solid and dotted curves) and southern polar flux (dashed and dash-dotted curves) from the same simulations.