of course, nowhere does it say whether these 30m are from side to side or from corner to corner.
i used a ruler on the image you posted, and from corner to opposite corner these are 2,5cm and from side to side these are 2cm
that's a 25% difference in distance. so if you make the opposite corners be 30m apart, then the sides are less than 30m apart.
you can fudge a bit with this, by making the aooposite sides be 30m apart and thus making the corners more than 30m apart.
but it still does not give much wiggle room for adjustments to the MWLL scales i guess . . And of course, the weapon ranges . . .