Does someone know something about international Edexcel exam fees, help!

Does someone know the rules about the fees?
The situation is that: I take the international advanced level in an Edexcel centre in China. In AS, the fees for each paper I have taken last year is 370 RMB per paper for Science subjects and, for example, other subject (ecconomics) needs 520 RMB for each paper. However, the price has increased to 400/each Science subject paper and 600/each other subject paper this year.
And for my friend in Cyprus, it takes 220 Euros (about 1600 RMB) for all A2 exams (3 paper)
For my other friend in China in another centre, it takes him 720 RMB for each Science subject paper and 1080 RMB for other subjects each paper like economics.
I don't know what the fees is to take Edexcel international advanced level in other centres.But it seems for us three the fees to take the same exam is quite different in different centres.
My question is: Is the exam fees policy made by the single centre, or there is an officail standard for the fees?(Edexcel International Advanced Level)
Please someone helps me,qaq, I will really appreciate your reply!