Do you need to take the advanced exam? Personally, I think it’s not always necessary. Of course it’s worth being able to speak English that well, but you can prove your level in other ways. For example, you can spend some time working in your field in an English-speaking country or finish a Master’s degree in English. You could also ask for your job interview to be conducted in English. The advanced exam is expensive, it takes almost all day (so you might just be too tired to show your real level of English) and to pass it you need to practice doing specific exam exercises rather than the type of English that you may really need.