I am using Microsoft Computer Vision API for OCR processing and I noticed that they are getting charged as S3 transactions instead of S2 in my bill.

I'm using the .NET SDK and the API I am using is this one. https://docs.microsoft.com/en-us/dotnet/api/microsoft.azure.cognitiveservices.vision.computervision.computervisionclientextensions.readasync?view=azure-dotnet
I have also confirmed that the actual REST API the SDK calls is the following POST /vision/v3.2/read/analyze https://centraluseuap.dev.cognitive.microsoft.com/docs/services/computer-vision-v3-2/operations/5d986960601faab4bf452005
According to documentation, that should be the OCR Read API, am I correct? https://docs.microsoft.com/en-us/azure/cognitive-services/computer-vision/vision-api-how-to-topics/call-read-api
I am puzzled as to why my calls are getting charged as S3 instead of S2. This is important for me because S3 is 50% more expensive than S2. Using the Pricing Calculator, 1000 S2 transactions is $1, whereas 1000 S3 transactions is $1.5. https://azure.microsoft.com/en-us/pricing/calculator/?service=cognitive-services
What's the difference between OCR and "Describe and Recognize Text" anyways? OCR (Optical Character Recognition) by definition must recognize text. I am calling the Read API without any of the optional parameters so I did not ask for "Describe" hence the call should be S2 feature rather than S3 feature I think.

I already posted this question at Microsoft Q&A but I thought SO might get more traffic hence help me get an answer faster. https://docs.microsoft.com/en-us/answers/questions/689767/computer-vision-api-charged-as-s3-transaction-inst.html



