When one engages a SEO expert on his/her e-commerce site, the SEO expert demands a full access to google analytics account in order to do his job properly. This is also his way for generating traffic reports to send it to the client. However, the access to google analytics also gives the SEO expert access to the accounts of the company. He has thus a full knowledge of how much revenue was generated in a month by the company. This knowledge then gives him a power to negotiate his SEO fees frequently with the company. He will start to think that the more revenue the company makes, the more his SEO fees should be. But any given company can only increase the pay of a SEO expert to a certain level. If the company's revenue doubles in four months after hiring the SEO expert, that should not mean that the SEO expert's fees should also double. The increase in the revenue could be due to other factors not related to the SEO experts work.
So what do you guys think? Is it fair for the SEO expert to demand increase in his fees because the company's revenue has gone up?