The primary reason for changes in all court parameters are the changes in gas prices. With respect to PoH, another reason for the change is the fact that the court has many single juror rounds, which is mathematically relevant, as mentioned here:
That being said, there is also a degree of subjectivity involved in these calculations when it comes to certain assumptions, such as in quantifying juror effort. You may refer to the document below and offer your amendments:
You may also experiment with the parameter calculator for coming up with alternative parameters: