Another, somewhat 'disruptive' data point....

Recently booked and flew LHR-NHD in J, via UK VS call centre.

Availability had been showing via UA, but then disappeared an hour or so before I got time to call up.

I thought I would have a chat with the call centre anyway. They advised it was worth sending a request anyway, as NH was making different availability to them since the Skyteam move that did not always match *A searches.

Availability was confirmed straight away, despite there not being availability showing on *A/UA in real time.

They seem to be restricting NH availability requests to 3 per call.