Variable Girth Enlargement

Consider an erect penis divided into 3 equal segments, starting from the base and ending at the coronal ridge. This results in 4 marks of division, visualized roughly here:

-1 2 3 4
8|=|=|=|D

The erect girth in inches at each division is as follows:

1) 5.00
2) 5.25
3) 5.50
4) 4.75

Then, consider the following changes to the girth here:

1) 5.00 + 0.50 = 5.5
2) 5.25 + 0.25 = 5.5
3) 5.50 + 0.00 = 5.5 (Note how the girth at this mark remains the same)
4) 4.75 + 0.75 = 5.5

Is such a transformation possible? And if so, how? Please give your reasoning. I am especially interested in real life anecdotes of the same.