Comparison of the measured positions of the BSCZ in the r₀₁₀ ratios with predictions of standard models (blue area) and models including a penetrative convection of 2 H_p for the three Kepler stars. The Sun is represented by the solar black symbol and Doris (KIC8006161) by the black star symbol. The models predictions are extended regions, rather than lines, because they included the position of the BSCZ from the zero age main sequence to the terminal age main sequence. The top panel presents the measurement with the standard fitting expression and the bottom panel presents the results with the non-sinusoidal fitting expression.