Help with rowshift needed

I have narrowed down the problem from my previous question.

I have a for loop

for ashift = 1:n

    x = [x(:,1) - x(ashift,1) x(:,2) - x(ashift,2) ...
    x(:,3) - x(ashift,3)]
end

which outputs four matrices (when n = 4) like so:

x =

         0         0         0
  -21.3131    8.6558   -2.5770
  -21.3446   15.1527  -11.0297
  -14.4331   16.9392    9.8923

x =

   21.3131   -8.6558    2.5770
         0         0         0
   -0.0315    6.4970   -8.4527
    6.8800    8.2834   12.4693

x =

   21.3446  -15.1527   11.0297
    0.0315   -6.4970    8.4527
         0         0         0
    6.9115    1.7865   20.9220

x =

   14.4331  -16.9392   -9.8923
   -6.8800   -8.2834  -12.4693
   -6.9115   -1.7865  -20.9220
         0         0         0

But I need the rows with zeros in to be at the top of the matrix to simplify subsequent calculations, so I am implementing:

rowshift = 0;
for ashift = 1:n
  x = [x(:,1) - x(ashift,1) x(:,2) - x(ashift,2) ...
  x(:,3) - x(ashift,3)];
x = circshift(x,rowshift)
  rowshift = rowshift - 1;
end

However for some reason this changes the order of the output, i.e:

x =

         0         0         0
  -21.3131    8.6558   -2.5770
  -21.3446   15.1527  -11.0297
  -14.4331   16.9392    9.8923

x =

         0         0         0
   -0.0315    6.4970   -8.4527
    6.8800    8.2834   12.4693
   21.3131   -8.6558    2.5770

x =

         0         0         0
   14.4331  -16.9392   -9.8923
   -6.8800   -8.2834  -12.4693
   -6.9115   -1.7865  -20.9220

x =

         0         0         0
    6.9115    1.7865   20.9220
   21.3446  -15.1527   11.0297
    0.0315   -6.4970    8.4527

You see the 3rd and 4th matrices are changing order. Can anyone explain why this is happening, and how to stop it from happening?

Kind regards,

Tom