RE: I only see a "Customize Report" button and when I click on it I have the column selection where I'm not able to find the "Other" field I'm looking for.

Yes, I see that as well. I had thought it available as the Other 1 and Other 2 table columns are.  One wonders.

The best I can suggest going forward is to create a custom field on customer records called "My Other" or something and then include it on your invoices or other sales transactions.  You can include this custom field on transaction reports.