I’m not making this stuff up, chillen:

“Reasons for Filing.
E: You filed or are filing a joint return for either 2005 or 2006, but not for both years, and line 8 above is smaller than line 5 above. You must file page 1 of Form 2210, but are not required to figure your penalty (unless box B, C, or D applies).
(For Paperwork Reduction Act Notice, see page 7 of separate instructions.)”