help understanding profiler results

Hi, I have this toy example code, that takes about 20 seconds to run on my machine:

A = randn(400, 257);
B = randn(257, 200);
C = randn(30, 50);
D = randn(50, 100);
for k = 1:30000
    A*B;
    C*D;
end
toc;

When I comment the A*B line inside the for loop, it takes approximately half a second to run. When the C*D line is commented, it takes about 20 seconds. However, when I run the profiler (on the original code), I get:

The running times do not correspond to what is obtained when each line is commented... Any explanation?

I run MATLAB 2012b on MacOSX-64.

Thanks

[dpb]

profiler takes overhead--it's not indicative of non-profiled code excepting in relative performance. It's intended use is simply to identify bottlenecks, not for absolute timings.