SVGT: clarification on currentScale and currentTranslate

Dear Scalable Vector Graphics Working Group,

  In http://www.w3.org/TR/SVG11/struct.html#InterfaceSVGSVGElement the 
currentScale property is defined in the IDL as:

           attribute float currentScale;
                       // raises DOMException on setting

But in the description below it reads:

        NO_MODIFICATION_ALLOWED_ERR: Raised on an attempt to change
        the value of a readonly attribute.

The attribute is not readonly. Furthermore there is no situation that is 
described where it should be readonly. In the case of inner SVG 
elements, the property (as defined) is accessible but still refers to 
the outermost scale. currentTranslate is defined as a readonly object, 
but does this mean that it's internal X and Y should raise DOMExceptions 
on setting (to match currentScale)?

Please clarify the wording about when or if the currentScale property 
should be treated as a readonly attribute and when it should raise and 
exception.

regards.
--
Jeff Rafter