On what basis system will take the last cost price? What will happen if the previous transaction happened with a Free Of Cost Item (0 value)? It will not be actuals most of the time.
As a simple process Inventory/Warehouse Team shouldn’t be bothered about the Weighted Average Cost at the moment during any Inventory Journal be it Counting, Movement or Adjustment. But for Finance, trial balance is the bottom line and inventory should be actuals always. Weighted Average is the simplest way of Inventory Costing used widely for Retail.
If the adjustment quantity is high we are never going to get the correct value of Weighted Average Cost.
It is difficult to convince the Customer if we don’t have a logic.
Kindly consider to share this feedback with the product team.
It may not be available instantly but should be taken on priority based on the Global requirement worldwide.