A strict reading of section 402A(c)(2) of the tax code appears to deem the excess first to be in the Roth account and only the portion of the excess that exceeds the Roth contribution would be in the traditional account:
(2)Designation limits
The amount of elective deferrals which an employee may designate under paragraph (1) shall not exceed the excess (if any) of—
(A)the maximum amount of elective deferrals excludable from gross income of the employee for the taxable year (without regard to this section), over
(B)the aggregate amount of elective deferrals of the employee for the taxable year which the employee does not designate under paragraph (1).
In your example, this would mean that you have $4k of excess Roth contributions and $9k of traditional excess deferrals. Only $9k would appear on Form 1040 line 1h.
