If the price of a Variant changes from your previous purchase, then you can maintain the new stocks in a new 'Batch' (without mixing with old ones).
Batch is a subset for the total quantities of stocks available in a variant based on buying and selling price. Each batch holds quantities, buying price, buying tax, selling prices, selling tax & HSN code.
Let us take an example.
The above Variant, Apple iPhone 6S 64GB Gold, has total of 33 quantities in available stock. This is in two batches:
- Batch2 - Quantities 15, buying price 48000 and selling price 58000
- Batch1 - Quantities 18, buying price 45000 and selling price 55000
Adding initial stock while defining the Item and Variant will create a default first batch named 'Batch1'. You can add the new stock purchases to the same batch (if prices are same) or create a new batch while purchase inward.