Thanks for the corrections!

I believe the 5th map, City Navigator SEA (I thought it was Southeast Asia not Southern) NT is not as updated as the specific City Navigator Singapore/Malaysia map. But the advantage of course is that it covers all the SEA countries, or most of it. But I seem to recall that for some coutries like Indonesia, it only covers certain cities.

I still do not know the answer to my original question, which is why the files for City Navigator map for Singapore/Malaysia is more than twice the Malsingmaps NT 2011 map with similar features. Could be due to any reason but I would like to know the actual reason so that I can decide which map to use. Personally, I would much prefer to use the most updated MSM 2012 map but unfortunately, there is no junction view yet. So, lack the cool factor!