What’s the difference between the “linked row limit” and the rest of the slope limits?

The difference is that “linked row limit” checks the slopes between two connected rows of the same link, for example: first and second row, second and third row, etc. Whereas the rest of the slope limits (N-S and E-W) check the slopes underneath each structure. For both cases, if a slope exceeds the set limit, the entire linked row is removed.