Controlling Change Bars with an Attribute

I am using FrameMaker 10 and I want to add a capability via an EDD that uses an Attribute to control the display of a change bar for a text range.

I have had success doing this for other font settings such as Underline, but when I try to use the Change Bar font setting the attribute will turn the Change bar on, but will not turn it off.

e.g.

Element (Container): Revst

General rule:    <TEXT>

Attribute list

Name: Document-Revision     String     Required

Name: Revdate     String     Required

Name: Rev-Status     Choice     Optional

Choices:    Current, Superseded

Default:    Current

Name: Source-Data     String     Required

Text format rules

If context is: [Rev-Status = "Current"]

Text range.

Font properties

Change bars: Yes

Else, if context is: [Rev-Status = "Superseded"]

Text range.

Font properties

Change bars: No

As I said, this works fine for underline, but fails for the Change bar.

Is this issue a known bug?