I guess it could be a balance choice, but Flame dash at level 3 with no items has a 20 second time between charges, and a 23 second cooldown. This means you can't really benefit from any charges on the ability as you're waiting nearly the full cooldown of 1 charge just to use your next charge.
With Transcendent cooldown, These invert with the time between charges on the tooltip staying at 20 seconds, but the cooldown is 17.2 seconds. Despite this, you can use the ability again after just 17.2 seconds.
With rapid recharge, the cooldown and charge separate a little bit at 14 seconds between charges and 19.8 seconds cooldown,
With both transcendent cooldown and rapid recharge the time between charges and the cooldown drop close together again with the cooldown being 14 seconds and the time between charges being 14 seconds and cooldown being 14.8 seconds
With Transcendent cooldown, These invert with the time between charges on the tooltip staying at 20 seconds, but the cooldown is 17.2 seconds. Despite this, you can use the ability again after just 17.2 seconds.
With rapid recharge, the cooldown and charge separate a little bit at 14 seconds between charges and 19.8 seconds cooldown,
With both transcendent cooldown and rapid recharge the time between charges and the cooldown drop close together again with the cooldown being 14 seconds and the time between charges being 14 seconds and cooldown being 14.8 seconds
