Yes same for the others too.

Only if follows to another <S1> or <S2> or <S3> levels only need to change as in would be change.

Example
<S1> AAA
<S2> BBB
<S3> CCC
<S4> CCC

Would be:
<S1>AAA
<S1-S2>BBB
<S2-S3>CCC
<S3-S4>DDD