Academic Writing - Thesis editing - Economic Analysis

A chapter of my thesis including economic analysis for an engineering process. Approximately 8000 words have been written by a non-native PhD student. At least requires a person understand engineering or economic. I try to explain the things on my own way but I have a feeling that the sentences that I had created looks so simple since I repeated the similar structure all the time. I am looking someone who can change the sentence structure to make it more advanced and clearer. For example, two sentences combined for one which makes the things more clearer or if there is another possibility to use different sentence rather than what I repeated.I am not asking to rewrite all the sections but I may expect you to understand at least 40-50% for a good proofreading. Like the last time when I gave another section for proofreading, I received 'a' and 'the' corrections only, since she could not understand the topic well, which I do not want to have it again. -only native English pls... -please do not bid if you are asking more than £40. -finally, there is no time limit and up to 3 weeks is acceptable -no payment before customer satisfaction