Relative difference between the spectra of the maps simulated with one and two instrument databases. The three curves represent power spectra relative to three different feed horn pairs in the 70 GHz frequency channel. A running average smoothing kernel has been applied to reduce the scatter and enhance any larger-scale trends. The relative uncertainties are of the order of ΔC_ℓ/C_ℓ ≲ 10^-4.