What deduction is incurred when a gymnast fails to maintain a horizontal position during a Level 4 bars cast?

When a gymnast fails to maintain a horizontal position during a Level 4 bars cast, the appropriate deduction is 0.20. This deduction reflects the importance of achieving a horizontal back angle, which is a critical element of the skill on the uneven bars. Staying horizontal indicates good form and control, which are essential for the execution of the cast. If the gymnast does not achieve this position, it suggests a lack of technique that could affect the overall performance on the apparatus. Therefore, a deduction of 0.20 is warranted to account for the degree of error in maintaining that essential position.