Description:
No, the impedance of HVOUT (in the open drain mode) and OUT port is not equal. The design for both the ports is different since HVOUT is designed for higher voltages (10V/12V) and OUT is designed for lower voltages(5.5V).
For example consider POWR1220AT8 Datasheet, as per the Digital Specifications on page 11, the current sinking ability for HVOUT is 10mA (in open drain mode ) and OUT is 20mA, which implies the impedance on both ports are not the same.