Andrew, thank you for your response and advice. I have read your another reply in given link. Actually, it was my fourth attempt and in previous tests also I scored low in Speaking section and it was my best yet (15-18-19-20). In the speaking section, I didn't like my performance after test is over and think that 20 is normal result for my responses. My performance for the speaking section was measured as fair in all three separate parts of speaking (independent, campus and lectures). I firstly thought about to choose which section to rescore, but chance of increasing 25 is unlikely compared to increasing 20, therefore I considered rescoring speaking. But I am more confident in writing than speaking, my performance for writing was measured as good in both essays, however I think my second essay at least would be given 4.5 which would increase my score to 27, but it is just risky to hope to get increase from 25 which is already good score. And here is my my detailed scores in the previous tests:
T1 - 85 (R-26, L-22, S-15, W-22)
T2 - 91 (R-27, L-21, S-18, W-25)
T3 - 97 (R-27, L-26, S-19, W-25)
T4 - 99 (R-28, L-26, S-20, W-25)
I hope it can give broader picture about my situation. Thanks in advance for your response.
BR,
Ayaz657