OAB - Pre or Post tax set up

Question

We are implementing OAB (from OSB). In OSB we have the pre and post tax elections done at the plan level -
For example, select:
Plan - Dental Plan Pre Tax
Option - Employee
In OAB we are considering setting pre and post tax at the option level -
For example, select:
Plan - Dental Plan
Option - Employee Pre Tax
Is there a difference between the two and does it matter which route we choose? I assume the only difference would be what the employee would see in self service (with the first way they see more plans and fewer options and with the second way they see less plans and more options). Or are we missing something?
Curious to know how others have their plans and options set up.

Answer 1

I'm not familiar with US Payroll, but if you look at the Model WTs for Country Code 10 (in V_512W_D) you should be able to find WT Models BA31, BE31, BP31, BR31, BT40 and M730 (I may have missed some).  Pre-Tax and Post-Tax setting could be Processing Class 65, but you should check the online documentation (help.sap.com or scn.sap.com/wiki) to confirm.
The IRS should be the source of information regarding US 401K plans, but you can also find information on Wikipedia (and elsewhere on the web).
As for where to do the configuration and which Infotype to maintain, I would presume that it depends on the Company's 401K Plan (Employee Deduction only or Employee+Employer Contributions), who manages it, and so on.
As I mentioned in your initial thread, please start by reading a little on the subject, such as
Saving Plans - ERP Human Capital Management - SCN Wiki