Often yes, because they are deliberately conservative and increased by a mark-up (10% in 2026, up to 30% in 2028 for steel, aluminium and cement). If your product is less carbon-intensive than this default value, supplying verified actual data reduces the bill. For a product more carbon-intensive than average, the choice needs to be costed.
Read the source article: CBAM cost: estimate import charges from 2026 to 2034