Is it possible for a safe harbor 401(k) plan currently using a standardized document to switch to a non-standardized document, without that switch triggering a requirement to file for a determination letter (as is required when a change is made to a prototype - standardized or not - that converts it into an individually-designed plan)? The employer is a Cycle D filer. The switch would be prospective, going into effect in caledar/plan year 2010. Thanks.

I assume you mean a non-standardized prototype, or a volume submitter document, that has already received an IRS opinion or advisory letter? If so, then I don't see a problem with this. You are generally allowed to rely on the opinion/advisory letter as equivalent to a determination letter, as long as you aren't doing something funky with the elections you make.

Yes, that is what I meant. Thanks.