No, you misunderstand the problem statement. Your results don't show the problem:

sgkirkup@7­2sp691lin:­~$ ./performa­nce-test.p­l 
Section A took 0.8600 CPU seconds
Section B took 2.1800 CPU seconds
Section A took 0.8800 CPU seconds
Section B took 2.2200 CPU seconds
[download]

The problem isn't that "Section B" takes longer than "Section A", but that the second run of "Section B" takes longer than the first run of "Section B" (and not just slightly longer).