It does. I'm not saying it shows NB made the call just that it was entirely possible for him to have done so before any shots were fired. Jurors were misled over this in that they were told JB entered NB/June's bedroom and opened fire with NB sustaining the facial wounds there. How could he then have made the phone call when the pathological evidence showed he was incapable of purposeful speech thereafter and had he attempted to put his mouth to the phone he would have transferred blood stains it.
The physical evidence at soc places NB on the landing stairs when he sustained his facial wounds so entirely possible he came up the stairs from the kitchen having made the call to JB.
They weren't misled, the defence could have brought that up at trial and didn't. It's basic commons sense to suggest that if a call was made, then it was clearly made before he was shot - his defence thought it best not to pursue - there must have been a reason.
It's also entirely possible that he pushed pass Bamber and there are other possibilities.