Going into the final weekend of the tax season, Internal Revenue Service (IRS) personnel are working long hours managing the rebate ripple effect. The agency has taken about 1,500 employees off their regular jobs to handle rebate-related calls, according to the Treasury Inspector General for Tax Administration's (TIGTA) interim report. The IRS also expects to pay for overtime and extend the employment of "seasonal" workers because of the added workload, the Washington Post reports.

As of March 8, the IRS's automated message-response phones had received 1.2 million calls about the rebate, above their normal volume for this time, according to the TIGTA report. Callers who normally would not file a tax return are provided with the option to get more assistance on how to qualify for a rebate, the Post reports.

The TIGTA report says that the number of calls about tax rebates would have been substantially greater if the IRS had not spent about $45 million sending advance notices to more than 130 million taxpayers.

IRS offices will be open until 5:30 p.m. in many locations for the rest of this week and on Monday and Tuesday of next week. Many local offices will open on Saturday, April 12th to assist taxpayers with incomes under $40,000 as well as those who are filing to receive the stimulus payment.