Thousands of widows and widowers were underpaid Social Security benefits after a mistake by the Social Security Administration , costing surviving spouses more than $50 million combined, according to a new federal watchdog report. The findings show that agency staff failed to properly calculate survivor benefits for an estimated 8,618 widows and widowers, resulting in average losses of about $5,800 per person. On top of that, the report found another problem that thousands more beneficiaries