RFE response submitted upgrading to PP

Hello ,

I submitted my RFE response in Feb -15 but haven’t heard anything back from USCIS . I raised 4 service request but only generalized response that “We will start working on your case”… No updates are available.

Question is :
Do I need to submit any document while I upgrade to Premium Processing or just Fees and form ?

I am not sure when you upgrade to premium processing after submitting your RFE response what supporting document you require.

IS it Advisable to submit my salary slips / pay roll for all this month to USCIS ?