I know this is an old thread, but seemed the most relevant without opening up something new item. I was able to do similar adjustments for the offset to a published service by just right-clicking the .loz file (...arcgisserver\directories\arcgissystem\arcgisinput...), choosing to edit in notepad++, doing a find on words like "offset" to get to an area I wanted to change, and than made the desired adjustment (set offset to 0.00000). I had to go in and do this as the offset values of the published service did not appear to honor the 0.0 side / end offset that the local version of the locator had.
This proved to be successful; however, any change I made had to contain the same amount of characters as what existed. If the # of characters for the overall document were changed in anyway, ArcGIS Server Manager would say the service was corrupted when trying to restart. Unpacking and re-zipping the files as you mentioned appeared to completely alter the .loz file and would run into the same corruption issue. It almost seems like arcgisserver does some sort of character count to see if the .loz file has been altered and considers it corrupt if there is a mismatch.
Is anyone aware of any other way to manipulate the .loz file for a service without running into this corruption issue? For instance, it could be convenient to slightly adjust some of the standard output fields (MatchAddress, ShortLabel, LongLabel) to better match an organizations workflows. This seemed possible, but would necessarily increase or decrease the overall # of characters for the file and would be seen as corrupt by ArcGIS server when restarted. This is unfortunate as a more robust ability to manipulate the .loz file could offer GIS administrators more control over customizing a geocoding service outside of the base options ESRI offers.