(1) All of the contributions are reported on Form 1120S. The employee elective deferrals must also be reported with code D in box 12 of your W-2; any Roth contributions would be reported on the W-2 with code AA.
(2) Elective deferrals are to be included on Form 1120S line 17, Pension, profit-sharing, etc., plans. Roth contributions would be included on Form 1120S line 8.
(3) Employer contributions are to be included on Form 1120S line 17, Pension, profit-sharing, etc., plans.
Your Form 1120S line 8 should include only the total amount reported in box 1 of the Forms W-2 prepared by your S corporation.
