PO oriented tax

Hi,

I was working in PO.The tax is being calculated after giving the condition values.

I need to change the value of a tax amount.after po creation..I dont know where is this value is stored.When i press F1,its showing that it is komp-mwsbp.

but this is a structure,i dont where this value is stored in table.

also i need to know where is the pricing details are stored,(Pricing table)

Cany anybody help me oput of this..