How is the effective minimum cell height for a row calculated?

I selected a cell in a row, but I found that its minimum height is not determined by itself, but by the cell with the most text lines in the row.
How can I use a script to find the cell with the most text lines in this line?
The minimum height of the red cell in the sample file below is 30pt. It seems that there is still an error in the calculation as follows:

CellH=14+14+2*1.417=30.834>30pt。

Another question, how to calculate the total height of the table columns in the current text box