FSG Create lines in between two lines

 Hi,

We are on Oracle 11.i

How can to do, to insert between two lines, one line of calculation and other of account assignments?. 

The problem it´s that the lines were created with a series of one on one and  there is no place  to create lines between two lines and the row set  is too big to have to redo.

Example

In the row set, I have defined lines 1, 2, 3 y 4 . I need to create two lines in the middle of line 3 y 4,  one line of calculations and the other of account assignments.

Thanks and regards,

Juan Pablo