I didn't mean to create concern with the colour comment. I like the blue. I checked the bottom of the closest piece I have to yours, a Seguso VA deeply-lobed corroso bowl from just a little after yours. It's cut straight across the bottom, extending out to the lobes. But mine is made from a single gather of glass, whereas it looks like yours is made up of at least two gathers. More importantly, the finish on the bottom of your bowl is very clean and neat.
Christine replied as I was typing this, and she certainly has more knowledge than I have, so you can be reassured by her comments.