Add "Since usable" in conditions, analogous to "Since ready"

[eranikid]

I would like my auras to briefly flash a glow when they come of cooldown. Luckily, there is a tool for doing exactly that: it's possible to set up a condition on "Since ready" as follows:

But there are some exceptions from this rule: for example the Hammer of wrath spell, which is unusable unless either target has 20% or less HP, or you are under the effect of certain buff. I would like my aura to briefly flash a glow in case any of the above conditions activate, but it is not possible - there is a "Spell usable" condition, but not "Since usable" condition, and "Since ready" is only triggered by cooldowns/charges.

It would be nice, if there either was a separate "Since usable" condition, or the "Since ready" condition could also check the time since spell became usable