1. The fact is that the reported return data already accounted for net expense ratio. So a fund performance is reported return + net expense ratio. Though it is easy to figure out 1 year performance this way, 5 year or 10 years performance is hard to calculate (because net expense ratio might be different over time).
2. do not compare apple to oranges. Different type of fund (growth vs. value vs. sector) have different cycles, so it is important to decide what kind of fund you invest based on your risk tolerance, and then compare performance of funds of same category.
3. Take a look at ETF, there might be a similar ETF that meets your investment need that are cheaper than mutual fund.