If you compare the figures posted by finance.gov.pk & the ones used by the IMF, they are very similar.
Let's compare the figures:
2008-09:
IMF: 677.793 billion rupees
finance.gov.pk: 720.6 billion rupees
2007-08:
IMF: 484.36 billion rupees
finance.gov.pk: 434.1 billion rupees (underestimated)
According to finance.gov.pk's figures, Pakistan has incurred losses of $13.56 billion in 2009-10, & $17.83 billion already in 2010-2011.
The losses added in these 2 years alone are about $31 billion. From 2004-2009, Pakistan incurred $30 billion losses. That's $61 billion from 2004-2011. From 2001-2004, Pakistan has incurred losses of about $7 billion. So that is exactly $68 billion losses Pakistan has had to incur from this WOT till today.
http://www.imf.org/external/pubs/ft/scr/2010/cr10183.pdf
http://finance.gov.pk/survey/chapter_11/Special Section_1.pdf