Hello Venkat,
I beilieve the Differentiation Critieria is at securities Account. Under Define and Assign Differtiations, make an entry for the product type under Single position management. Then it will consider the product type to be checked with whichever consumption sequence you have defined.
As per your previous config, the system calculated Gain/loss on a weighted average basis. Hence also try checking by creating a new securities account and ID. The previous securities account would be locked as transactions exist which would be handled through Weighted average method.
regards,
Nikhil