“Perfection” is not a standard of care. No design professional should be required to deliver against such an unrealistic expectation. When such language arises in any proposal or agreement, be ready to take two actions: (1) strike and re-draft the provision; and (2) talk with the Owner to assure a more reasonable goal.
Designers are compensated for professional services few can deliver; they are not paid for perfection. Communicate this distinction with confidence.