Goods Issue amount difference

Hello,

I have two examples where I am not able figure out about goods issue posting amount and can not co relate with CKMI1-moving average price and amount calculated (CKMI1-WRBTR).

While posting goods issue user entered 22638.21 $ in external amount LC field for 6000 quantity. Now after entering all other fields ( GL/cost center/plant/storage loc) he saved it. Now accounting entries are posted as below,

PK--99----amount --$ 19604.72

PK--81  ( GL entered in account assignment)--$ 22638.21

PK 96--Purch price difference account --$ 3033.49

Now when I checked tables MSEG and CKMI1 table I found that total stock before this transaction was 926 and total value was $ 460.34 and having said that moving avg price would be 49.71 for 100 qty. So why not goods issue amount for PK 99 was calculated by 6000X .4971= 2982.76.

I am not able to figure out from where 19604.72 got calculated.

Regards