The 180 + 10 only applies if you are staying onsite in a Disney resort.
All guests can make ADR's at 180, regardless of where they are staying or even in they are locals. The Plus Ten is a perk for onsite resort guests. It lets you book, at the 180 day mark from your check in, the next 10 days worth of ADR's. It is a nice advantage. Not all seats are released to the 180 + 10. So if you are not successful, call back at exactly 180 for that restaurant, as more tables are released then.
Have a Great Trip