Hi Mohammad,
We are also using the same Datasource and it is running as Delta 8 times a day during month close from ECC to BW to BPC and 4 times in regular days.
I don't understand your problem why you are doing full load even if these two data sources are delta enabled.
are you using 0FIGL_O10 DSO or you have created any custom DSO?.
How BPC delta process works:
BPC Delta process captures the BW request ID as reference for next load and if you have deleted BW data and request that means you have broken BW->BPC delta links and that's why you are getting this issue.
If you are deleting and re-load BW data then you need to do BPC as full instead of delta.
Thanks
Obaid