[Vaughn]

...The Glass ones I got at the same time as the plastic one did corespond in measure, so they were well worth the extra cost.

Don't know if this is the situation, but the plastic ones I get have both US and British ounces marked...you might have a mix-up of units!

I certainly like my glass graduates -- I use a lot of acetone and it eats the plastic graduates! I also have a couple Kodak glass beakers -- on the bottom they say "For Photographic Use Only Kodak" -- the words are cleverly arranged so that what one sees when quickly looking at it is "Only Use Kodak"!