Hi Jalina,
Am not sure which field indicates "amount paid".
Below are the fields amount fields from the DS - 0FI_AP_51.
WRSHB - Foreign currency amount with +/- (its from tables BSIK, BSAK)
NETT0 - Net amount in foreign currency (, its based on some fields from thsese tablesBAIK and BSAK,its calcualted)
ABZUG - Cash discount mount in doc currency with +/- (From table BAIK and BSAK,its calcualted one)
RWBTR - regulated amount in currency of payment (PAYR -RWBTR)
RWSKT - Overall account of payments transaction in currency of payment ( PAYR - RWSKT).
Extrcator was using this prorgam to extract, SE38 - RFCHKN10.
Please check this below one. might be useful.
http://help.sap.com/saphelp_nw70/helpdata/en/db/0345943f9043e083c3ccba1e73b42a/content.htm
Take abap help and debug the prorgam or extractor and take FI team help also.
Thanks