Your loop on IT_BSIK_TEMP is inside the loop of IT_BSID_TEMP, so you are adding the entries of IT_BSIK_TEMP again and again for every entry that is checked in IT_BSID_TEMP. From your question and looking at your code the exact requrements are a bit unclear. In the question you mention adding the entries from IT_BSIK_TEMPand IT_BSID_TEMP table but what you are really doing is combining the records from IT_BSID_TEMPand IT_BSIK_TEMP.
I suspect you might get what you want if you add the conditions from the READ on IT_BSIK_TEMPo the loop at the same table. Once you have done that you can remove the READ and the check on SY-SUBRC.
You would get better answers if you spell out your requirements clearly.