Effect of contributions to a SIMPLE and a 401(k).

[Guest]

An employer maintains a SIMPLE IRA during January and February. It the terminates the SIMPLE and starts a 401(k) plan. Can a SIMPLE be terminated during a plan year? Bigger problem, since the SIMPLE is not the "exclusive" plan for 2000, are the contributions to it excess contributions? Does the 4973 excise tax apply? Could all deferrals to the SIMPLE be distrbuted under the 408(d)(4) rules before the filing of each participant's tax return? Real situation. Thanks.