The size of overall assets in your employer's 401k plan makes a huge difference. The larger the plan in overall assets (pulling all the participant funds together) means the plan sponsor can negotiate better expense ratios for you. If those fees are correct, they are very, very low and mean a lot more money for you in the long run. Unfortunately those that work for smaller companies pay much higher fees which erode returns.
You mentioned the flat quarterly administration fee. This goes towards things like keeping Fidelity's website available to you, manning the call center, sending you account statements, performing calculations and record keeping and may also include mandatory fees like paying for annual audits. More Plans are going to this and it is a good thing for people with high balances. Before a switch of this kind, people with high balances essentially subsidize these administrative fees on behalf of the folks with low balances because the fees are paid out of credits that go to the employer. You don't even see them or know it's happening. Kudos to your company for making the administration fees equitable for all!