The Pentagon announced Tuesday that the accounting error revealed last month was significantly more than previously stated and aid provided to Ukraine was overvalued by $6.2 billion rather than $3 billion.

The accounting error includes fiscal years 2022 and 2023 and occurred because "in a significant number of cases," when the US transferred weaponry, military officials counted the value of replacing the weapon instead of the value of the actual weapon, deputy Pentagon press secretary Sabrina Singh explained at a news briefing.

That process drove up the cost of each new aid package -- because new weaponry costs more than old weaponry -- and resulted in the false assumption that more of the funding had been used.

"In a significant number of cases, services used replacement costs rather than net book value, thereby overestimating the value of the equipment drawn down from US stocks and provided to Ukraine," Singh said.

The final calculation of the accounting error is far higher than the Pentagon previously estimated in May, when it first revealed the miscalculation as $3 billion.

"We have confirmed that for FY23, the final calculation is $3.6 billion, and for FY22 it is $2.6 billion, for a combined total of $6.2 billion," Singh said. "These valuation errors in no way limit or restricted the size of any of our PDAs or impacted the provision of support to Ukraine," she added.

The extra $6.2 billion is likely to mitigate the need for Congress to pass an additional assistance package before the end of the fiscal year in September.

The White House told CNN last month that it is not currently planning to ask Congress for new Ukraine funding before the end of the fiscal year at the end of September, which has pitted administration officials against some lawmakers and congressional staffers who are concerned that the funds could run out by mid-summer.

The first accounting error of $3 billion revealed last month triggered frustration from Republicans on the House Foreign Affairs and Armed Services committees, who believe the mistake reduced the amount of US support that went to Ukraine leading up to the counteroffensive.

"These funds could have been used for extra supplies and weapons for the upcoming counteroffensive, instead of rationing funds to last for the remainder of the fiscal year," wrote House Foreign Affairs Chairman Michael McCaul and House Armed Services Chairman Mike Rogers in a statement last month, when the first $3 billion accounting error was publicly disclosed by the Pentagon.