Oh, OK. I thing I understand what you mean.
In a short words: you need different thread fields.
In a long words:
Notice that I always use
data after the input words?
Each row of Job Position - Job Type - Quota of Labor is a set of data. It means that each row may contains different set of data, even the data type is the same.
The same exact question is, why you need another textbox for the Company Name, Quota of Labor and the Salary while there is already a textbox for thread title (subject)?
Because you need different layouts? Nope, you can modify the layout or the appearance of them individually directly inside the newthread/editpost templates.
For example:
The answer is because you need different data.
I'm sorry for my lack of ability to understand what you mean.