Disambig n-best scores

[Roy Bar Haim]

Hi,

How is path score in disambig with n-best option calculated?

For example, suppose that I have the sentence:

W1 W2 
Which is tagged with T1 T2

Then I calculated the path probability as follows:

Log10 [ P(T1|<s>)*P(T2|T1)*P(<\s>|T2)*P(W1|T1)*P(W2|T2) ]

I got it "almost right" . I checked for two paths:
For one I got -20.549 (while disambig returned -120.549)
For the other I got -20.837 (while disambig returned -120.837)

What is the reason for this difference? Should I always ignore the "1"
after the "-"?
Thanks,
Roy.