Condition type value can not be changed in PO pricing

I have created PO which is having pricing procedure consisting different condition type. When i create any subsequent document (MIGO or MIRO) and realized that condition value in the pricing need to be changed so I have reversed all subsequent document so that can carry out "update pricing".

when i press Update pricing button on the condition tab, its showing message that new pricing can not be carried out. I observed that some condition types of pricing are grayed out.

Kindly help to solve this problem. Kindly help me how to 1) update pricing or 2) can change value of condition type.

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