Personally, I would still prefer the extra accuracy, all this does is make it less obvious that the numbers are different, it doesn't actually change the situation that, from the players perspective your cooldowns are most likely wrong, if not misleading.
I mean if we take a spell with 0.5 seconds as a base, anything under 10% won't show a change, and 11% would suddenly show a 20% decrease which doesn't exist, whilst DPS would be showing correct numbers that your displayed cooldowns have no relation to.