Yup - your firing bullets, it happens!
First time I was on an ETR as a "stalker" the 200m Figure 11 targets looked good with the naked eye at the firing point but when you looked at them through the scope when they resembled a sieve! Good enough for the squaddies to aim at but trying to requal at 200m presented a little bit of a challenge. Our RCO-agreed solution was for firers to centralise the vertical crosshair on the Fig 11 and set the horizontal crosshair on the shoulders. Stepping through the shots on the Toughbook showed little spread and the overall grouping size was easily measured electronically. My take away from that, subsequent ETR shoots and use of the Bisley targets is that the "target" is immaterial, you just need to have a consistent POA and leave it to the electronics taking the display view as the "target".