Journal Entries posted between MM-FI

Hi,

I have a clarification with JE posted in background between MM & FI.

1. Raw Material sent for production

Raw Material consumed a/c DR 15000

Inventory RM a/c CR 15000

2. Finished goods recieved from production

Inventry FG Dr 20000

Change in Stock Finished Goods Cr 20000

3. Finished goods sent to Customer

COGS Dr 5000

Inventory Finished goods Cr ?????

My doubt is in 3rd JE, what is the purpose of debiting COGS (DR) against Inventory FG account (CR)? What happens to the Change in Finished Goods account?

Please explain with amount which I assume I may not have given the correct figures. But I want to understand this entire cycle with correct amounts debited and credited along with the respective GL accounts.