NIW and EB1

[aspire_gc]

My case has been filed for NIW and EB1 recently.
Few days back I received I797C notice.
On first page there is a section 'notice type'. It says - "Section: Indiv w/Adv Deg or Exceptional ability in the National Interest"

So my question is ..
1. Do we get separate I797C for NIW and EB1 filing or just one I797C?
2. What avg. time USCIS takes to process Eb1 filing?
3. I am planning to upgrade Eb1 filing for premium processing. Will I get a new I797C once USCIS receives the check?

thanks in advance!