Hi Kalyan,
Thanks for sharing the report summary. It looks like you are comparing the total stats at the account level with stats related to keywords. They will have discrepancy as both the reports are not the same. To compare the stats specific to keywords in the API and the UI, you will need to follow the steps mentioned below:
For each client account :
From the UI : navigate to the client account, choose keywords tab, make sure there are no filters set on the UI, select the correct date range and check the totals on that UI view.
The costs and other stats from the UI and the API should match for each account. To get the stats at MCC level, you will need to aggregate the values obtained from the API and UI. Please check
this guide to understand how UI reports are mapped to the API reports. Please give this a try for one or two accounts and let me know if you face any issues. If so, please share the UI screenshot for that account along with the report definition used via API. You could use reply privately to author while sharing the details.