Calendar year DB plan terminated as of 12/31/02. Plan had a funding deficiency for 2002, and sponsor is paying excise tax. Plan is terminating in a standard termination thanks to substantial owner waiving benefits.

If the funding deficiency is never corrected, are there potential additional penalties even though there is no longer a funding standard account maintained after the termination?

See Revenue Ruling 79-237. I believe it essentials states that no additional 10% penalties apply for plan years after the year of plan termination, however, the 2002 plan year deficiency if not corrected will be increased to 100% under IRC 4971(b), if not corrected.

Seems unlikely that the 100% penalty could apply if the plan is terminating in a standard termination.

Revenue Rulings can be located here:
http://www.taxlinks.com/rulings/findinglist/revrulmaster.htm

Pax, I'm not sure practically speaking how this really plays out (if 100% always gets assessed), but the critical paragraph in that Rev. Ruling is:

"It should be noted, however, that a termination does not relieve the
employer of the obligation to fund the accumulated funding deficiency as
of the end of the plan year in which the plan is terminated. If this
deficiency is not reduced to zero, the 100% penalty tax imposed by section
4971(b) of the Code will apply".

Since the entire Rev. Ruling is only dealing with terminating plans it's hard to see why they would state that if it just goes away.