I have Mk1 and a Mk3. The Mk3 is a replacement. The first Mk3 had very large gaps between 40 and 55 yards but the image quality was very poor. The replacement has very small gaps but clear and reproducible (so far) in ranging finding. Gaps similar on Mk1 and new Mk3.
Tend to adjust the wheel of the Mk1 at the start of a match to allow for temp. Just setting up the Mk3 (at 5C), so hope that the gaps remian similar when the temp goes up.