How should I sort my data?

[jjbigfish]

I have an attached example file. I am looking to sort column B by size. The issue that I am having is that when I select to sort by column B Z-A for largest to smallest, it doesn't put it in that order, the first SKU 15505 comes in correct, with the largest being first, but the second SKU 19208 doesn't sort by largest size, the largest row comes in at row 30. How should I go about fixing this?