Entry FPLT does not exist in (check entry)

Hi Experts,

I use invoicing plan in framework order. But I need to remove the invoicing block using BAPI_CHANGE_PO. When I used invoicing plan type 10 (sample periodic invoicing plan) the function module worked nicely. But I faced an error when I used invoicing plan type 20 (sample partial invoicing plan) like this saying that entry FPLT does not exist but in fact it's already exist.

This is how I fill the INVPLANHEADER data:

This is for the INVPLANHEADERX data:

This is for the INVPLANITEM data:

and this is INVPLANITEMX data:

Invoicing Plan data already exist when I checked the table.

I would really appreciate some help and advices because I need to fix this problem.

Thank you.

Best regards,
Riky