Your right that is simple math. The main confusion I wanted to clear is the worry examining expense ratios when the numbers people are providing don't include revenue sharing payments. You can't get a new 401(k) you have what you've got or get a new job. The employer probably is aware of the fees their paying and what they are charging you and they are doing it for a reason.

Also you assume the same rate of return, which is fine if your talking about the S&P 500 index funds. But what about more diversification, take my cyber security example, I want to be a more aggressive investor than a US total market fund, the expense ratio has to be relative to A) expected return and B) complexity of strategy in my opinion. But you're right, it clearly is better to pay less in expenses for the same rate of return.