From the design concept proposed here, it is not clear whether the columns that show the nested content appears only when the row containing the nested content is expanded or not.
Also, if you have sorting functions on the table (which is standard for most data tables), how does that affect the behaviour of the rows and columns?
In general it is not a good idea to combine multiple design patterns together, or couple them too tightly in a particular feature or function because it leads to less flexibility later down the track.
Of course, if you have a very specific user requirement and this proves to be the best way of solving that problem, then you have some reasons to deviate from convention.