Retirement tax questions

Per this article from the IRS Individual 401-K plans , when you contribute to an individual 401(k),  your elective deferrals are limited to the overall $58,000 for all 401-K plans, as it says it is limited "by person, not by plan" :

However, this does not seem to apply to a SEP contribution, so that is why your contribution in TurboTax is not being limited. Your advisor might be referring to an individual 401(k) contribution when he mentioned the $58,000 limit.