This is excellent news for Ukraine's war effort. The US still has plenty of capacity to ensure Ukraine has the weapons it needs to fight off Russia and launch its counteroffensive, without facing the red tape of further approval from Congress.
Despite wishing the world to think it stands in solidarity with the Ukrainian cause, the US administration is expecting conflict with Russia to continue for years or even decades, as Kyiv will be very unlikely to deal a mortal blow to its enemy. The US has saved face internationally by encouraging the continuation of war, including by supplying Ukraine with weapons, when it knows that a negotiated settlement would be best for everyone. News of this accounting error will not benefit Ukraine, only spur on a deadly conflict without affecting its outcome.