I am a lower-intermediate player and played "real" badminton only since last year. I have been using BG65 for 21lbs (newly strung tension) for 1 year. Now I think the tension already drops to less than 20lbs. The strings move every time I do a full smash, or even a clear. Now I want to change to BG70PRO at 24lbs. Will I experience much change in power in the early stage and after a few months?