A sponsor has an existing safe harbor uniform allocated profit sharing plan. They want to start of new DB floor offset plan--also to be a safe harbor plan. Are they required to consider the existing DC account balances, or can they count only future employer contributions? What are the options?

Both. See 1.401(a)(4)-8(d), specifically 1.401(a)(4)-8(d)(iv).

Are you saying that "the offset under the defined benefit plan must be applied to all employees on the same terms" is the authority to design the offset anyway one wants as long as the terms are the same for all participants?

Thanks for your reply.

Designing the offset "anyway one wants" is far too general and I am not saying that. For example, I don't think it would be permissible to offset the DB by $1,000 for every tooth in a person's mouth. But both your options in your first post are available.

I'm glad to see that these boards do not advocate discrimination against incisor-impaired individuals.