Ah, disregard my previous calculations. In your case your maximum permissible total contribution is $24,686, of which a maximum of $22,500 is a combination of employee elective deferrals and Roth contributions, and $2,186 [not $2,168 that I originally typed) is employer contribution. Because you already contributed $8,000 as a Roth contribution and $2,050 as a traditional elective deferral or employer contribution, that leaves $14,636 that you can still contribute as a combination of employee and employer contributions. If you contribute that all as a combination of traditional elective deferral and employer contribution, that would give you a total self-employed retirement deduction of $16,686.
