27 Miss. Code. R. 220-XIII-13.2
A Participant whose employment is interrupted by qualified military service under Code Section 414(u) or who is on a leave of absence for qualified military service under Code Section 414(u) may elect to make additional contributions under Article IV upon resumption of employment with the Employer. Such additional contribution shall be equal to the maximum amount that the Participant could have deferred during that period if the Participant's employment with the Employer had continued (at the same level of Compensation) without the interruption or leave, reduced by any amounts deferred on behalf of the Employee during the period of the interruption or leave. Such additional contribution shall be made no later than five years following the resumption of employment (or, if sooner, for a period equal to three times the period of the interruption or leave).
27 Miss. Code. R. 220-XIII-13.2