DFVCP fee

If filing for a client 5 years of 5500s for a DB plan with the DFVCP, can you charge for this service. What is reasonable?  Hourly rate for the time spent on this?  Thank you for any thoughts.

well how much are you actually doing? sending them a link to the DFVCP page and telling them how to answer the questions? and then telling them to click okay and follow the instructions to make the online payment? 
Seems like that's just an email, or maybe a phone call if they like someone to be with them while they click on things. 
Assuming you are charging for preparing the 5500s themselves, and marking the DFVCP forms, I don't see how it would be much more. 
If you charge by the hour for extra assistance items, maybe one hour? 

As @justanotheradmin notes, you need more information about the DFVCP and your role.  Here are some things to consider:

• Does the plan sponsor have in hand the Schedule SB Actuarial Information and all of the related attachments for each plan year?  If not, who will coordinate gathering this information from the actuary?
• Does the plan require an audit for any of the plan years?  If yes, does the plan sponsor have in hand the completed audit report for each year?  If not, what role if any, might you have in working with the auditors?
• When filing retroactively under DFVCP for more than 2 years past due, the plan will have to use a current year form to report the earlier years AND will have to use the prior versions of any Schedules that needed to be attached to the original filings for each year.  See                        https://www.askebsa.dol.gov/FormSelector/ to get a flavor for how this works.

In some ways, this is the tip of the iceberg, so you may get drawn into things like determining if appropriate fidelity bond coverage was in place, or tracking participant counts, or filing Form 8955-SSA, ...

A reasonable fee not based solely on hours spent, but also includes recognition of the knowledge and expertise you bring to the process.