There are two types of Job Seekers Allowance (JSA), Contribution and Income based, You must be in receipt of Contribution based JSA which as the DWP say is only available for 182 days.
You should now be eligible for Income Based JSA if you do not have a great deal of capital, your partner does not work over 24 hours a week, if you have one, and you are available for work. The amounts payable for the two types of JSA are the same.
The deductions will probably be that some income has been received, which has changed your applicable amount, or deductions, which can be made from IB JSA, usually fines, council tax arrears or child maintenance.