Credit Card Programs - Amex Business Card App

I'm thinking about applying for a amex business card (Delta Gold) online and I had two quick questions.

1: How do I input my ssn into the EIN field in the business section. It has two fields (XX XXXXXX) so I don't know how I would put my SSN into it correctly. Would I use just the second or both (the first only has space for 2 characters)?

2: Is there any reason not to put non business related expenses on an amex business card? (ex. personal flights not related to the business)

Thanks

Just use your SSN, putting first two numbers in box one and the rest in box two.

The main reason NOT to use a biz card for personal expenses is because biz card charges are not protected by Fair Credit Billing Act and you can be very unhappy about this if a problem comes up.

My policy, use biz card to extent needed to get bonus miles, otherwise use personal card.

Makes sense. I was thinking to just use it to purchase flights to be reimbursed by my employer to get the bonus miles/priority boarding then stop using it. I'd put everything else on my personal spg.