@Ashwin Venkatesha Thank you for posting this question on Microsoft Q&A.
The calculation posted in question is incorrect.
1GB = 1024 MB
Thus, in this case,
12000 requests/Min * 1MB is not equal to 1.2GB/min. It would be about 11.7GB.
However, as per the limit, the "Maximum data/minute per DCR" is 2GB.
Hope this helps.
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