Here are the Luminance Grids
for calculating Lseq. of all three standards:

In all three standards
there are 9 rings and 12 (radial) sectors.

The UNI11095 2011
grid weights the upper and lower fractional sections by their reduced
area.

The CIE88 2004
has the "tallest" grid but the uppermost and lowermost areas
are not used in the calculation, as they are considered to be outside
a normal person's field of view.

The UNI11095 2003
grid did not take into account the fact that the upper and lower areas
are smaller, but it did have a wider aspect ratio.

UNI11095 2011
introduced a maximum curve above the minimum curve, presumably to encourage energy saving as well as luminous uniformity: