Consider the following macro:

    run("Bat Cochlea Volume (19K)");
    run("Scale...", "x=1.0 y=1.0 z=0.5 width=121 height=154 depth=57"
        + " interpolation=Bilinear average process title=bat-cochlea-volume-1.tif");

Now when trying to make it more generic by leaving away the explicit `width`, `height` and `depth` parameters:

    run("Bat Cochlea Volume (19K)");
    run("Scale...", "x=1.0 y=1.0 z=0.5"
        + " interpolation=Bilinear average process title=bat-cochlea-volume-1.tif");

you'll notice that the image is not scaled any more. In fact the default values calculated for `width`, `height` and `depth` for the current image take precedence over the provided factors `x`, `y` and `z`.
I would expect the provided parameters to always take precedence over any parameters that are not explicitly given and filled in automatically.

Information about your version of Java:

  os.arch => amd64
  os.name => Windows 7
  os.version => 6.1
  java.version => 1.6.0_24
  java.vendor => Sun Microsystems Inc.
  java.runtime.name => Java(TM) SE Runtime Environment
  java.runtime.version => 1.6.0_24-b07
  java.vm.name => Java HotSpot(TM) 64-Bit Server VM
  java.vm.version => 19.1-b02
  java.vm.vendor => Sun Microsystems Inc.
  java.vm.info => mixed mode
  java.awt.graphicsenv => sun.awt.Win32GraphicsEnvironment
  java.specification.name => Java Platform API Specification
  java.specification.version => 1.6
  sun.cpu.endian => little
  sun.desktop => windows
  file.separator => \

The up-to-date check says: REMIND_LATER

Information relevant to JAVA_HOME related problems:

  JAVA_HOME is set to: C:\UTILIT~1\FIJI-D~1.APP/java/win64/jdk1.6.0_24//jre
  imagej.dir => C:\UTILIT~1\FIJI-D~1.APP

Information about the version of each plugin:

Activated update sites:
ImageJ: http://update.imagej.net/ (last check:20150915154157)
Fiji: http://update.fiji.sc/ (last check:20150928150247)