Maths Prediction

Okay so I got 238/300 in Maths when 240/300 is an A for AS. However my teachers will only predict me a B when I really need an A. Are they being very harsh in not predicting me an A and is there anything I could do to change their mind? C1: 69/100 (will resit) C2: 98/100 S1: 71:100 (will resit) Hopefully will get 90+ in both the resits which leaves me only needing 200/300 next year for an A. Thanks in advance for any advice/ help!