401k In Plan Roth Conversion Limitations

I have conflicting guidance on this issue. So long as a plan allows, can anyone convert all or a portion of their 401k accounts (including all pre-tax sources - deferral, rollover, employer) at anytime?

Some suggest that only those eligible for in-service distributions (typically age 59.5) can covert to Roth. Others are suggesting that anyone can convert but only taxes can be withheld for those that are eligible for in-service.

This is obviously only an issue for active employees, not terminated employees. 

The plan document will say. Look at the actual adoption agreement (if there is one) not just the SPD. 

Some are written to limit conversions only to people/sources that are eligible for distribution. This is similar to the older rules of in-plan-Roth rollover. 

Others are written to not limit conversions to people who are eligible for in service withdrawals. 

What does the document say?

we explicitely allow for conversion of VAT at age 35+ to accomodate Mega Back Door.  This is for solos.

In-plan Roth Conversion (IRC) just means changing pretax money to Roth money. 
 

In-plan Roth Rollover (IRR) means the money was available to be distributed before the conversion. Many RKs limit IRCs to this type.

In-plan Roth Transfer (IRT) means converting the money but it wasn’t available for distribution and you have to maintain the distribution restrictions of the money source. Many RKs don’t want to do this and have to track that many different sources.