Coving - excessive adhesive and dodgy corners?

Had walls & ceiling skimmed and some coving fitted. Not happy with the look of it: - there's a very thick bed of adhesive between the cove and the ceiling, 5~8mm, around the entire room (it's not gap fill). Plasterer claimed this was "the only way to do it". - He's also "had to" shave down the width of the coving on the way into some of the corners to make it meet properly. He's done that from about 6 inches out from the corner, looks obvious and frankly ugly. With the previous coving in that room and in the rest of the house, the front edge is almost flush to the ceiling (maybe 1mm adhesive bed visible) and has no nasty corners, they all fit neatly. We're far from happy with the look of the new work. Is he right, or did I choose the wrong tradesman?