Is retroactive spousal support retroactive from the date of separation retroactively retroactive?

The Wife argues that retroactive support should date back to the date of separation. But at the time of the separation, there was no indication whatsoever that the Wife claimed spousal support (though her entitlement was obvious). The law is clear: entitlement alone is not sufficient notice of a claim: Kerr v. Baranow, at para. 208. There has to be something more to make out effective notice.