So normally when someone gets paid consulting income, the accountant will then turn around and produce a Schedule C since there is most likely some sort of expense related to the consulting company (for example, accountant's fees to prepare return.)
Therefore, for example, owned original business from 1/1/2000 and sold 8/1/16 under a S-Corp and owner made over $265,000 max comp. Let's call this company XYZ Trucking Company. Has 4 other employees and owner contributed max $60,000 under 4k/psp plan. Owner (John Doe) owned 100% of this company up until 8/1/16 and sold 100% of company to national firm.
Then paid from 8/2/16 to 12/31/16 consulting income via 1099 non employee compensation which the accountant turns into a Schedule C. This would be called John Doe Consulting with different tax id. Wants to max out the compensation from this company as a SEP. John Doe owns 100% of this company.
Not sure if this helps.