I have the salewa crow and the la sportiva trango trk. Also a couple pairs of scarpa boots. Salewa and sportiva are both size 46. Salewa calls that a 12, sportiva calls it a 12.5. scarpas are 46.5 and that box also reads 12.5. I am sitting here now in some Salomon size 12s that also read 46 2/3....? I usually consider myself a size 12 across the board.
It's not very universal sizing depending on the brand. I'd say the salewas are true to size and you'd probably want to size up by a half in the sportivas....and order from somewhere that will exchange....