thank,
i had pasted Cost based code no worrries.
so next code will be item mapping
LS_AREA_TO_ITEM_MAP-ITEM_GUID = LR_ITEM_TO_CCTR_MAP->ITEM_GUID.
APPEND LS_AREA_TO_ITEM_MAP TO RT_ITEM_TO_AREA_MAP.
so as per you after this code system will take care about Porduct category based arroval , the way cost base working.
Like this product category exist in which other line items so sum up all these line and bring in WI subject line.