There are 7, not just 3
Main Ones
Type 1 – Overwrite
Type 2 – Add a row
Type 3 – Add a column
Variations
Type 0: Retain Original
Type 4: Add Mini-Dimension
Type 5: Add Mini-Dimension and Type 1 Outrigger
Type 6: Add Type 1 Attributes to Type 2 Dimension
Reference