Surprise Uber fees

Lately, I have been getting surprise uber fee's. I would take a pool expecting it to be around $7-10, but when I get charged, it ends up being $17-20. When I send screenshots to uber, they tell me I was charged appropriately, and that a surge charge took place. However, my screenshots say otherwise. Additionally, I have noticed an average $15 increase in my prices vs my girlfriends. Meaning, we both attempt to call an uber from the same location, and same time, but hers is often $15 cheaper than mine. I have brought this up to uber as well with no success.