Indian GST calculated wrong

[Equelle]

Hi, 

My products are with a GST of 12% and is included in the product. however Shopify calculates it wrong. From example below the tax amount should be 660 ( 12% of 5500) but it calculates as 589.29 ... Please can anyone kindly help me out with this. 

[lynth]

Hi, are you sure you configured it correctly in settings/markets/select country/taxes?

[Equelle]

Hi, Thanks for your quick respoonse. Yes we have configured it as per the screenshots below. 

[Equelle]

The GST formula is GST Amount = (Selling Price x GST Rate) / 100. 

Where can I check if this is used maybe ? 

[lynth]

Maybe this will help you:
https://www.youtube.com/watch?v=wCbOME28Aik
https://www.youtube.com/watch?v=kkGv_4eJDiM 

[Equelle]

Thanks for the videos, We have set up everything accordingly. Only the amount calculated is shown wrong as mentioned earlier. Is there a method to check what formula Shopify is using to calculate GST ?