i have a same problem what you are facing, my problem my inventory consist of expiry date

STOCK NAME EXPIRY DATE UNIT PRICE
A 01-08-2008 100 $ 1,158/-
A 02-09-2009 120 $ 1,268/-

STOCK CONSUMED 120
CLOSING INVENTORY 100 WHAT FORMULA I USE?

Similarly
STOCK NAME EXPIRY DATE UNIT PRICE
B 01-08-2008 100 $ 1,458/-
B 08-09-2009 80 $ 1,368/-
STOCK CONSUMED 120
CLOSING INVENTORY 60 WHAT FORMULA I USE?

CAN YOU HELP ME OUT?