Top panel: IQ variation for 100 ke⁻ (peak) spots after having redistributed the charges (on a range comparable to what was presented for DECam on Fig. 3). The accuracy of the approximation of the interpolation method (in red) is compared with the result found using the exact charge density (in blue). Bottom panel: residuals. For an IQ of 1.6 pixel, such as 550 nm spots on CCD E2V-250, the approximation introduced an underestimate below 0.1% on the size of the spot, which is less than 5% of the amplitude of the effect.