Since 6.2.0, GetActionCooldown no longer gives information about Action charges:
local cdstart, cdduration, enabled, charges, maxCharges = GetActionCooldown(action)
local cdstart, cdduration, enabled = GetActionCooldown(action)
The only way to get info about Action Charges is:
Lua Code:
local charges, maxCharges, chargeStart, chargeDuration = GetActionCharges(action)