Calcualting JSA from part time work

Hello,

I just started a part time job. Its 3 days a week, 8 hours a day, 8.65 an hour!!

This gives a weekly amount of 207.60, using a tax calculator it said that after prsi It amounts to 203.16. Is this correct?

working on those figures I worked out that my daily earnings are 28.63 (203.16/3 = 67.72 - 20 x 0.6)

If I multiply this by 3 this gives 85.89!! Is this the figure I will get in JSA payment or is 85.89 taken from my 188 JSA claim to give me a payment of 102.11 from the JSA.

Please if anyone can advise it would be greatly appreciated.

Additional info: I started the job this week and will be on a back week, also my JSA payment will be delayed as they change me over to casual labour and backdated a couple of weeks, and I have just finished a 9 month jobbridge internship last week so things are going to be tight with no income coming in for a few weeks to say the least!!