http://www.sbstransit.com.sg/press/2012-07-08-01.aspx
Seems like no one posted about this article about SBST
buying another batch of 1000 buses? It's just in.
"Delivery from as early as Jan 2013"..."comprising 450
award-winning Mercedes Citaro buses and 550 Volvo B9TL Wright
buses.." 
"Of the 1000 new buses, 260 will be funded by the Government under
the Bus Services Enhancement Programme (BSEP), while SBS Transit
will fund the (other) 740 buses under its growth and replacement
plans."
This article means:
1) King Longs are not bought by the Govt for SBST after all, so
probably the ones we're seeing is just a trial that was rejected by
SBST totally?
2) Depends on whether you like Citaros or hate it, there's gonna be
more Citaros. Damn. I expect more flamewars here
now.. 
3) The case of more Wrights mirrors the scenario of the VO3xs Batch
1/2/3s in the 90s..except their bodies all look the same. I don't
expect them to change their EDS any further to differentiate the
different batches as of now..