I'm with Lisa, I don't want my clients later getting a bill from the IRS, Makes it look like it was ME that didn't know what I was doing.

Keep in mind that anyone needing a 2210, almost always has to write a check. Your clients are much different than mine, if they are in a hurry for their return so they can write a check February 11, instead of April 14, (15,16,17,18...whatever the **bleep** date is extended to this year for whatever stupid reason)