Update:
Applied for Sponsorship in June 2007.
ECAS update showing decision made, letter sent to me (not received yet) on May 4, 2010.
Since my ECAS status says decision made, I will assume that they will not request updated Option C printout or any other documents.
So the PArt 1 of the process is done, I sent them the option C printouts from 2006 and 2007 when I applied back in June 2007.
However, the document checklist for Singapore Visa office, IMM 3057 E, Page A-2, Number 6, request for Sponsor's Additional Information as follows:
6.SPONSOR'S ADDITIONAL INFORMATION
•Your sponsor's income tax assessments for the past 2 years
•Letter from your sponsor's current employer stating his monthly income and position
•Welfare statements / unemployment statements ( if applicable)
So When I do send my dad's PR application (Part 2 of Process) I would definitely include my updated Option C printouts from 2008 and 2009. Updated wage statement letters as well.