Hi Nalini,
You should no touch spliting mehods because it's standard of system.
System will calculate the correct amount if you consider WT 2001 at end of schema. For this issue consider how system does it in X AL9 sun-schema in international verion of schema X000 or find the same sub-schema is related to your country version.
Here system determine "monthly factors" by PCR XPPF. You will find two factoring items. Imagine you have a splitting in IT0001 at 10th of a month which has 30 days. In this case the first factoring item will be 10/30 and the second one will be 20/30. Then system will times these amounts to related values of WT 2001. As you see you will have two items of WT2001 but the sum of them will be the same as original amount
Regards,
Omid