They lost 4 months of intensive ammo including precision Iskander missiles in the last 3 days.
It looks like Russia moved its air defense to protect oil depots/refineries and Ukraine has responded by taking our large ammo dumps with their own bunker busters/drones.
Zalenski is trying to show Biden ahead of their meeting this month of the effectiveness of static targets in Russia. The Biden administration has insisted that Russia has moved all targets away from the radius of their ATACMS missiles.