ITC clarification reg

Dear Sir,

When there is a changes in the GST tax rate as per recommendation of GST council , how the differences in tax amount will be treated by business entity?

Example:
1. M/s. ABC limited purchased Lithium Iron Batteries by paying the input tax rate of 28%.

2. The goods are available with stock.

3. Before liquidation of these stocks, now the tax rate has been reduced to 12%.

4. After this tax rate changes, that company can sell these goods with newly reduced tax rate.

5. How this situation has to be treated by this company?

Kindly explain.