Highly likely. There is another thread dealing with reduced packaging as a way of disguising price increases. My example was a 500 g box of Kellogg's cornflakes which now only contains 450 g.
I'll stick with Asda's own brand. (Not the 'value' one though, where the bean-to-juice ratio is definitely inferior). At just 24p per can (when you buy a pack of 4 for 96p), they're at least as good as the major brand names.