Analyzing the data, several potential causes for performance issues in the process can be identified:

1. Multiple approvals: In several variants of the process, the declaration is approved by multiple parties (Administration, Budget Owner, Supervisor) or the same party multiple times. This can cause performance issues due to inefficiency and delays as the declaration gets stuck at different stages of approval.

2. Rejections: Another notable variant causing performance issues is when a declaration is rejected either by Administration or Supervisor, then resubmitted by the employee. The repetition of the process can result in a performance decline as it adds unnecessary steps and causes delays.

3. Involvement of PRE_APPROVER role: It seems that involvement of a pre-approver in the process generally leads to longer performance times. This might be caused by unnecessary duplication of work or slow response times.

4. In some of the process variants, declaration approvals and rejections seem to be happening in a cyclical manner causing the increase in process completion time. This suggests that the process might not be clearly defined or properly understood by the participants.

5. The process variant in which the declaration is saved by the employee but not submitted is resulting in zero performance. It indicates that there is no process for handling saved but not submitted declarations, which can lead to performance issues. 

One of the extreme values of poor performance is directly caused by the Supervisor rejecting the declaration and the process is further stalled by the missing role interruption.

Remember, these are potential causes - validation with additional data or context might be needed to confirm these as actual root causes.