Thank you once again. Shouldn't that come up when I do a /nui help?

It should do, its been around for a while so Im sure it would have been added to the list at some point.

I search through the /nui help and did not see that any where.

From the FAQ "What slash commands does nUI support?"

• /nui hplost
  
  This option toggles display of the health bars on unit frames between health remaining (decreasing) and health lost (increasing). This is of particular value to healers.

Hopefully that explains it.

Thank You!