Benefit restoration under USERRA

[Guest HRAdvisor]

For purposes of granting military leave service under a defined benefit plan, how far back in time must be examined to determine missing service periods? Certainly under USERRA effective since 1994, I could see adding military service hours and pay to determine the correct accrued benefit. What about for service prior to 1994? We're hearing some suggestions to go back basically forever, but that would be a nightmare from an administrative perspective. Do you think that 1994 is an appropriate and/or best practice and/or acceptable practice?