Top panels: multipole moments measured from one mock parent catalogue (black continuous lines). The contribution to the overall clustering from the sub-samples of observable (blue dashed lines) and unobservable (red dash-dotted lines) pairs (defined respectively as those targeted at least once and the ones never targeted in the ensemble of 2170 targeting runs) as written in Eq. (16) are also shown. The combination of these two contributions is plotted as green filled markers. Bottom panels: fractional offset of the contribution from observable pairs and the unobservable/observable combination with respect to the reference measurement from the parent mock. This measurement refers to the low-redshift bin 0.5 < z < 0.7. The measurement in the high-redshift bin 0.7 < z < 1.2 shows a very similar behaviour.