Sorry, I meant high contention on the lock – if they plan on using a coarse-grained lock, I presume it will see high contention (assuming they have many statistics).
Obviously if they plan on using one lock per statistic, this isn't a problem, but then they should just be using atomic updates instead.
You're right, but it doesn't sound like these are high-contention operations since they currently run without any locks and rarely have problems.