After-tax Contributions and the ACP Test

I want to make sure that I understand the ACP test correctly. Example:

• Safe Harbor Plan - 3% non-elective
• No matching contribution
• After-tax contributions are allowed

If the NHCE ACP is 0%, then no HCE can make an after-tax contribution. 

If the NHCE ACP is 2-8%, HCEs can make after-tax contributions of the NHCE average plus 2%

If the NHCE ACP is above 8%, HCEs can make after-tax contributions of the NHCE average x 1.25

If so, it sounds like the sponsor would need to add some form of a matching contribution (possibly only to NHCEs) if they want to offer the ability to make after-tax contributions. 

Correct.