Understanding the Calinski-Harabasz Formula by simple example

Hi statistician, the Calinski-Harabsz (CH) is based on the variance. Basically this formula is used to score the clustering algorithm results. I try to understand the formula by simple example. Please help me to verify this.

Let say we have 10 object with 2 attribute and the final cluster after executing the clustering algo(example has 3 cluster):

This is the formula of CH:

The details calculation in the excel file in the link:

Please help to look into and comments. My problem is, it seems wrong since this CH index will gave big number such as 100 or 400. However, based on my calculation, the index will get small value such as 0.6 or 0.7.