Not sure if I totally buy the tooth age accuracy. I killed a black bear that was 6.5ft long and weighed a bunch. WDFW aged it as 1yr old from tooth. This boar was no one year old.
Wdfw didnt age it, they sent it to a lab to be aged. That being said, cementum aging isnt 100% accurate. I read where qdma took a number of deer of known ages and sent teeth off. I believe they used 2 different labs. They would send terth from the same deer to two different labs and quite often got different results. Results were pretty commonly a year higher or lower than the deers actual age, and sometimes off by 2 years. In your case of a large bear being aged at 1 year, its also possible that teeth got mixed up. A neighbor killed a very large boar that the results called 2 years old. Not possible.
Cementum aging gives you a good idea, but its not perfect. Generally if they say an animal is 5 yrs old for example, its a pretty good bet that its 4- 6.