Unpaid duty to paid duty

Dear GTS Experts,

We can make the goods unpaid customs duty to paid customs duty By Using closing potion option in BWH .

But,Sap provides this function module  /SAPSLL/API_IVMS_IDUP_SYNCHto make the goods from unpaid customs to paid customs.

Please let me know the difference between both of them.

Thanks a lot

Venu gopala reddy