cBlockArea

[xoft]

It should work normally, but the coords are 0-based, so your for-loops should be a bit different:

for X = 0, BlockArea:GetSizeX() - 1 do
    for Y = 0, BlockArea:GetSizeY() - 1 do
        for Z = 0, BlockArea:GetSizeZ() - 1 do

You were probably reading out of range, that's why you got 178.