I think you missed this clause:
“(iv) APPLICATION TO ELIGIBLE RETIREMENT PLANS.—For purposes of applying the provisions of this subparagraph in determining the amounts required to be distributed pursuant to this paragraph, all eligible retirement plans (as defined in section 402(c)(8)(B)) other than a defined benefit plan shall be treated as a defined contribution plan.”.
Useful references:
section 402(c)(8)(B)):
(B) Eligible retirement plan
The term "eligible retirement plan" means-
(i) an individual retirement account described in section 408(a),
(ii) an individual retirement annuity described in section 408(b) (other than an endowment contract),
(iii) a qualified trust,
(iv) an annuity plan described in section 403(a),
(v) an eligible deferred compensation plan described in section 457(b) which is maintained by an eligible employer described in section 457(e)(1)(A), and
(vi) an annuity contract described in section 403(b).
408. Individual retirement accounts
(a) Individual retirement account
For purposes of this section, the term "individual retirement account" means a trust created or organized in the United States for the exclusive benefit of an individual or his beneficiaries, but only if the written governing instrument creating the trust meets the following requirements:
(1) Except in the case of a rollover contribution described in subsection (d)(3) or in section 402(c), 403(a)(4), 403(b)(8), or 457(e)(16), no contribution will be accepted unless it is in cash, and contributions will not be accepted for the taxable year on behalf of any individual in excess of the amount in effect for such taxable year under section 219(b)(1)(A).
(2) The trustee is a bank (as defined in subsection (n)) or such other person who demonstrates to the satisfaction of the Secretary that the manner in which such other person will administer the trust will be consistent with the requirements of this section.
(3) No part of the trust funds will be invested in life insurance contracts.
(4) The interest of an individual in the balance in his account is nonforfeitable.
(5) The assets of the trust will not be commingled with other property except in a common trust fund or common investment fund.
(6) Under regulations prescribed by the Secretary, rules similar to the rules of section 401(a)(9) and the incidental death benefit requirements of section 401(a) shall apply to the distribution of the entire interest of an individual for whose benefit the trust is maintained.