differnce in stockvaluation

dear goru

good eve

whenever i check material stock through mb5b for a some material specially finish goods it shows diffrent value for same material

suppose there is mat A having prise 10 Rs/Kg

some time for 10 kg it shows value 100

some time for 5 kg it shows 70

even for zero stock it shows some value

in mm01 under accounting tab prise control ( V ) and moving avg prise is zero maintained

material type is finish good

do the needful

ple help

thank u

prakash