Grading the proposed list of questions with assigned confidence scores, I would give it an 8.5 out of 10. Below are the reasons for my evaluation:

### Strengths:

1. **Relevance and Coverage**: 
   - The questions encompass a broad range of themes pertinent to the process, such as workflow, approval hierarchy, reasons for rejection, time intervals, performance scores, and feedback mechanisms. This illustrates a solid understanding of the common challenges and information requirements related to expense declarations.
  
2. **Detail Oriented**: 
   - The questions inquire about specific aspects of the process, like roles of individual approvers, impact of budget owner approvals, contesting decisions, and optimizing submissions, which are crucial for a comprehensive understanding.

3. **Practical Focus**: 
   - Several questions target actionable insights (e.g., how to avoid rejections, documentation required, training provided) that can be very beneficial for both employees and administrators in improving the process.

4. **Technology and Policy**:
   - Some questions address the influence of automation, company policy, and regulations, reflecting a forward-thinking approach.

5. **Transparency and Fairness**:
   - Questions about contesting decisions, feedback mechanisms, and internal auditing practices demonstrate a commitment to maintaining a fair and transparent process.

### Areas for Improvement:

1. **Depth and Specificity**:
   - While the questions cover a broad spectrum, some might benefit from increased specificity or examples to clarify their practical application. For instance, "What are the common reasons for a declaration to be rejected at each stage of the approval process?" could involve asking for specific reasons from historical data.

2. **Complexity and Clarity**:
   - Some questions, though important, are complex and might be simplified to aid understanding. For instance, "How is the performance of the expense declaration process measured, and what improvements have been identified through these metrics?" involves two distinct areashow performance is measured and what improvements have been identifiedthat could be separated into individual questions.

3. **Priority Setting**:
   - Having a large number of questions is good, but categorizing them into high-priority and secondary might help in channeling focus and resources more effectively.

### Individual Scores and Justifications:

1. **Typical Workflow**:
   - Scored high because understanding the standard workflow is foundational (95% is justified).

2. **Levels of Approval**:
   - Very relevant for structural understanding, hence high confidence (90% justified).

3. **Reasons for Rejection**:
   - Highly useful for pinpointing submission issues (85% justified, but could be more specific).

4. **Time Intervals**:
   - Tracking efficiency is crucial (90% justified).

5. **Rejections by Approvers**:
   - Useful for identifying training needs or systemic issues (80% justified).

6. **Performance Scores**:
   - Insights into quality differences in submissions versus rejections (85% justified).

7. **Expense Categories**:
   - Better understanding approval nuances (80% justified).

8. **Effect of Budget Owner Approvals**:
   - Relevant to see how fiscal constraints affect approvals (85% justified).

9. **Role of Supervisor**:
   - Important given their final approval authority (90% justified).

10. **Feedback Mechanism**:
    - Feedback mechanism helps improve future submissions (85% justified).

11. **Contesting Decisions**:
    - Ensures transparency and fairness (90% justified).

12. **Optimizing Expense Declarations**:
    - Empowers better submissions (85% justified).

13. **Required Documentation**:
    - Clear requirements reduce delays (90% justified).

14. **Automated Systems**:
    - Enhancing process through technology (85% justified).

15. **Policy and Regulation Impact**:
    - Adaptability to changes is crucial (80% justified).

16. **Employee Training and Guidelines**:
    - Well-trained employees ensure smoother operations (90% justified).

17. **Performance Metrics**:
    - Insights into monitoring and improvements (85% justified).

18. **Internal Auditing**:
    - Oversight and control mechanisms are key (80% justified).

19. **Confidentiality and Data Protection**:
    - Extremely important in today's data-centric environment (95% justified).

20. **Payment Delays and Dispute Resolution**:
    - Ensures there is a clear path to resolve issues (85% justified).

### Summary:
The list of questions is comprehensive, relevant, and well-thought-out, covering most aspects of the expense declaration process. Minor improvements could be made to increase specificity, clarity, and prioritization. Hence, an overall score of 8.5 out of 10 is fair and reflective of the quality and depth of the proposed questions.