xml defaults and overwrites?

I am able to set the default values for controls in my XML .pres files by using <member name='ctl_str' value=x/> when placing controls.

When I initially deploy the device, the default values are used. When I rerun the properties the default values from the xml file are not used, rather the existing value is kept. In general this is a good thing (I don't usually want to erase my work on filter and level settings by going back to the default). However, sometimes it would be beneficial to go back to the defaults (like tonight, when I am editing a file made by another where all the HPF are set to 800 instead of 80Hz and I am dreading changing 250 fliters embedded deep in hierarchical blocks...).

Would it be possible to choose to use default settings or current settings when running properties? (The normal mode would be to retain current settings.)

On a related note, I have a .pres xml that lays out flyoffs using stock placeholder names.

                       <xpp:define name='sym_args'>
                        <member name='name' xpr:value="PGM Input" />
                        <member name="color_rgb" value="16711680"  />
                        <export xpr:name='"PGM"+i' />
                      </xpp:define>
                               <xpp:insert name='sym_point' />

I then go back and edit the names for the specific application. In this case, when I run the properties on the block, all of the flyoff names are replaced by the default placeholder values, effectively erasing my work. In this case I would like to also have the choice of using the defaults or retaining my current values.

Thanks!