The years demonstrate the amount and magnitude of the errors. If a punishment was life in prison, and the person had done two of those, that’s two life sentences. For example, if someone was facing 519 years for the same crimes as above professor, it would indicate the amount of which they have been accused of. A person can commit much more crime than a remaining lifetime worth(75 years realistic max)of imprisonment time. Similar to el chapo being charged more than a sicario, even though the sicario would have most likely done things that if convicted also warrant life in prison.