Tuition Reimbursement

Employer provides tuition reimbursement for employees. When reimbursement payments are processed, taxes will be withheld, however employer does not wish to have it be subject to 401k deferral contributions. How do we characterize this payment so that it is not subject to deferral contributions?  

Document defines compensation as 3401(a) - Are tuition reimbursement payments part of Code §3401(a)?

What are their best options here?

I have searched around and see that Taxable Fringe Benefits such as certain tuition reimbursements are included in 3401(a) - but I don't know what "certain type" means.  Not sure what question to ask.
 

13 hours ago, Becky Schwing said:

taxes will be withheld

My understanding is 3401(a) compensation is any amount upon which withholding is required, so I think this tuition reimbursement is included.