The CurrentValueFormatted field includes raw value formatted followed by the units, whereas the CurrentValue just shows the 'raw' value.

When CurrentValueFormatted Shows ** ERROR **

If the units field in the point object contains a single quote ('), then it will cause a formatting error and the ** ERROR ** message will be displayed.
If you wish to have a single quote in your units field, you must use the single quote twice, i.e. '' and this will output a single quote.