Material to Material Transfer Posting

Hi experts,

I would like to perform a material to material transfer posting using movement 310.

Material A at USD20 Moving Average Price

Material B at USD30 Moving Average Price

The transfer posting was done from Material A to Material B with quantity 10 to the same plant and storage location.

The account posting from this posting is as below:

Cr Material A USD300

Dr Material B USD300

I would like to know whether this posting is valid? What is the logic behind this posting?

I was expecting the account posting like, for example:

Cr Material A USD200

Cr Difference USD100

Dr Material B USD300

Appreciate if anyone can further explain on this.

Thanks and regards,

JT