@Aditya Kommu Welcome to Microsoft Q&A Forum, Thank you for posting your query here!
If you are looking at the total calls metric of your document intelligence resource. The number of calls in this case is the sum of all calls to the service i.e calls through training, analyze operation, management of models like list models, copy models etc. You will have to use the filter operation to lookup the OperationName property or dimension to understand the number of calls made for analyze or other available values.
The Processed Pages
metric, on the other hand, specifically refers to the number of pages that have been processed by the service.
If you are looking to calculate cost per document, the default metrics do not provide this capability to filter by document. Document Intelligence is billed by pages analyzed. When a document is submitted for analysis all pages are analyzed unless a page range is specified with the "pages" parameter in the request.
You will have to enable diagnostic settings to lookup requests made to each document and then compute the cost per document. Usually, if you are request is successful you are charged for each page depending on the number of pages successfully processed in the document.
Please refer the pricing page of the Document Intelligence: https://azure.microsoft.com/en-us/pricing/details/ai-document-intelligence/
Hope this helps. If you have any follow-up questions, please let me know. I would be happy to help.