The the "Employer Matching Contributions" box is also for profit sharing contributions to the individual 401(k). However, since you've already maxed your elective deferrals for the year with another employer, it would be better to enter the $6,000 as a SEP or Profit Sharing contribution on the Keogh, SEP and SIMPLE Contributions page since entering it as a 401(k) employer contribution will not allow TurboTax to limit the deductible amount to only the permissible employer contribution. The calculation for SEP and Profit Sharing contributions is the same as the calculation for the employer part of an individual 401(k) and is reported in the same way on Schedule 1.
