How to Setup 457/401 base plan and catchup plans to use a single shared election amount

Has anyone implemented deferred compensation 457/401 base and catchup plan deductions being managed by a single contribution election on the employee side? Ideally the employee would just have one deduction to maintain and the amounts would flow into whichever base/catchup element applies for a given payroll. This applies to EBS 12.2 Advanced Benefits/Payroll.

Standard functionality is that the employee enrolls in a deferred comp 457/401 base plan and a catchup plan, and then maintains 2 contribution/element amounts. The catchup can be taken concurrently with the base plan amount, or sequentially which doesn't start until the employee has reached the standard limit. When setup sequentially, on the payroll date where the employee reaches the standard limit the catchup also starts and both deductions are taken. This causes the employee to have a far greater deduction taken on that check than was intended.