The National Archives (NARA) provides free access to their Archival Databases.There are a large variety of records there, including the WWII Enlistment Records. (I know I've browsed through their records before, but I hadn't double-checked the data I had previously retrieved from Ancestry.com.)
They list my great uncle, Mandell's occupation as salesperson, which suggests the person who entered the data at Ancestry.com did mistake a '175' for a '170' (see previous entry). It also suggests that there was some way to indicate on the record which of several occupations in a particular category applied.
Confirming this is that a first cousin of my grandfather, Cruvant Altman, was a lawyer. He was classified under category 22 on his enlistment record. On Ancestry's record it says correctly, "Barber or Lawyer". However, NARA is more specific with "Lawyers and Judges".
Neither provide the image of the original document, but it looks like NARA's records provide better detail.