How to show summary value of a measure based on Item?

Summary:

We need to calculate summary value of a measure based on Item

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Hi Experts,

Need your help in achieveing following requirement in our project.

We have a custom measure which is entered by user.For this custom measure, we need to calculate summary value & ratio at same level based on Item Number. I've shared an example in the post. 

We've explored available functions and couldn't find any that could be used. Any pointers on achieveing this requirement will be very much appreaciated.Thanks in advance

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