Pivot shoes

The depth of my pivot shoe measures at 17/32.
The options I see for parts are either 1/2 or 9/16.
I am inclined to think I should order the 9/16 based upon the note calling stating that the 9/16 is decimal equivalent .540 (over a half inch).
According to the stickers on the windows, they are:
Series Number 0401-Double Hung
Product Line Number 004 018

I an quite certain these are Andersen windows, the double hung variety with only a half screen.
The part number (on swisco website) is 15-215 for the 9/16 pivot shoe shown.
The warrantee sticker inside the widow casing states they were installed in February of 2003, so they are old, but not ancient.

Based on the information above, should I choose the 9/16 or the 1/2 depth pivot shoe?

Paws Up !
Jacob