It's true, hence the '...up to a maximum of 100.' part. Although I don't know the specifics, from testing I've found that each class has 100 affinity for its own abilities, naturally. It also seems that THM has 80 affinity or so for CON abilities and vice-versa. DoWs have worse affinity for CON abilities, but I'm not sure if it's the same for all DoW. Someone could probably make an educated guess if they had all these affinity traits by looking at the cooldowns of abilities.