If the pattern calls for a bulky (sounds like it does) then you might need about the same. It's hard to say because of your own tension, actual thickness of the yarn, needle size, etc. You may even decide that your chosen yarn looks better knitted at more or less stitches per inch than what a label or pattern suggests.
Also depends on the pattern stitch; a lacey pattern will use less yarn than a solid garter or stockinette. Your pattern and yarn label probably refer to gauge of a solid pattern, usually stockinette, even if the actual vest itself is knit in a more open pattern.
I do a lot of sewing, and my rule of thumb when in doubt of needed yardage is to buy 10-20% more than called for. Better to have some left over than run out and not be able to match it later. But I am still a newbie knitter, so don't know everything about yarn just yet.