Hi Rose,
Here is the form back to use: https://acrobat.com/#d=R1qsHYR1bY6-wGZNElVARg.
The issue was that you were using absolute references to the Hours field: "form1.page1.Table.Table1.Row1.Hours" (or something like that).
When dealing with repeating rows, if you just reference the field name in your script, then each instance of that row will know that the script is referring to the object in its own row: "Hours".
Also in your script you are doing the same calculations several times. I am recommending that you do the calc once and assign it to a variable. From then on you are using the variable.
Hope that helps,
Niall