getObject() is actually explained on the
scripting page of the wiki (near bottom of page).
I'm not sure why you would want to access it like that though? It's a lot more confusing than the regular getObject() access method or the relatively new shorthand access method.
What Sebastian wrote in is example shows you that you need to break the quote to be able to insert the id's into the getObject("path"), which is just as messy as typing out the words or variables themselves. On top of that... I'm not sure if it's possible to combine multiple id's together to create a full path?
tid = game.SavedObject:getId().tableId -- store table id
oid = game.SavedObject:getId().id -- store object id
offset = getObject("(" .. tid .. "," .. oid .. ").ObjectOffset")
print( offset.x, offset.y )
vs ... offset = game.SavedObject.Offset
print( offset.x, offset.y )
Personally I like to keep things simple. I don't have the best of memory so being able to type in English is great for me as it allows me to quickly read over my scripts & -- comments to see what's what. But each to their own!