Difference of various structural quantities between a modified model and a reference model calculated with the MONSTAR stellar evolution code. The reference model is evolved from the ZAMS with microscopic diffusion and step function overshooting mixing over a distance d_ov = α_ovH_P, CB below the convective boundary. Lower panel: results for α_ov = 0.15 and upper panel: for α_ov = 0.20. The models with a modified temperature gradient in the overshooting layer (same microscopic diffusion and overshooting mixing treatment as the reference model) are evolved similarly from the ZAMS. The convective boundary is indicated by the vertical solid line.