This has been a common complaint across multiple vehicles across multiple generations. Fuel tank shapes and fuel gauge behaviors vary greatly. Also, in later generations, it can be averaged out to reduce gauge movement. If gauge progression is smooth, and consistent (with itself, and not necessarily what you think it should be), it'* likely working as designed. If the gauge jumps around a lot (not to be confused with fuel slosh of earlier generations) all on its own, whether it be all the time, or when it hits a certain point, then there is likely an issue in need of addressing.
I do not believe you have an issue that requires addressing just yet, however if there is an issue, it could be either the cluster (again), sender, or wiring. Also remember too that GM gauges are notoriously inaccurate, even when working properly.