Sure..... The spouse became disabled during 2010 and started drawing social security. So did her minor children. Their social security was included on the parents return which in effect increased their taxable income and disallowed the $1,000 child tax credit that was due them in addition to increasing their income taxes. Rental income (real estate) was reported on Schedule C rather than Schedule E causing the taxpayers to pay SE taxes needlessly. On the Sch C was listed the name of a government agency as the DBA name. The government agency was the payer of the rent on the 1099-Misc. The state return left off a deduction for taxable disability income the spouse received as well as a tax credit for the loss of the use of limbs, as well as overlooking a couple of other smaller credits.
The $4,000 difference is not uncommon at all with that local office. I cringe whenever I see an HR return come through my door. :o