Mid-Year safe Harbor Merger

[PMC]

Company A maintains 2 separate plans - Profit Sharing and 401(k) Safe Harbor (using nonelective). Both calendar year plan years. They want to merge them effective 11-1-09. Setting aside whether that makes sense with only 2 months left in the plan year, is it permitted?

The existing 401(k) Safe Harbor does not provide for any Employer contributions other than the SHNEC and a discretinary Match, so if they wanted to add a PS feature to the 401(k) that would be a change to the provisions mid year and that may prevent a merger mid-year.

What if the 401(k) doesn't permit any other contributions or changes to the Plan mid-year and it's basically the PS assets merging into the 401(k), would that make a merger acceptable?