The two DTSs are not equivalent.

DTS1 starts at dts1216a.xsd
DTS2 starts at dts1216b.xsd

The diff paths are:

[EvRelationshipFrom] Param[1]:Item: ConceptA Param[2]:Item: ConceptA
  [EvPrevious] Param[1]:Relationship A->C : in DTS1 previous is A->B, in DTS2 previous is empty.

[EvRelationshipFrom] Param[1]:Item: ConceptA Param[2]:Item: ConceptA
  [EvDelete] Param[1]:Relationship parent child A->B

[EvRelationshipTo] Param[1]:Item: ConceptB Param[2]:Item: ConceptB
  [EvDelete] Param[1]:Relationship parent child A->B

[EvRelationshipTo] Param[1]:Item: ConceptC Param[2]:Item: ConceptC
  [EvPrevious] Param[1]:Relationship A->C  in DTS1 previous is A->B, in DTS2 previous is empty.


DTS1 starts at dts1216c.xsd
DTS2 starts at dts1216d.xsd

The diff paths are:

[EvRelationshipFrom] Param[1]:Item: ConceptA Param[2]:Item: ConceptA
  [EvDelete] Param[1]:Relationship: (ConceptA) to (ConceptB)

[EvRelationshipTo] Param[1]:Item: ConceptB Param[2]:Item: ConceptB
  [EvDelete] Param[1]:Relationship: (ConceptA) to (ConceptB)