I don't know where that equivalence number is coming from., but it doesn't sound quite right in this context.
Whole hops alpha acids take a little longer to dissolve and isomerize because the lupulin glands are intact. Some of the extraneous plant matter is removed in T-45 hops and nearly none is removed in T90.
Wet hops have a lot of water as part of their weight (they're WET!
). Dry hops have about 25% the weight of wet so the ratio is about 4:1. If you'd use 1 oz of regular dried hops to bitter, you'll need 4 fresh.
Whole hops tend to hold more wort than pellets. That's where the 10 oz number you cited makes sense. But if you use a hop bag, most of that can be drained back out.
Most homebrewers tend to use homegrown hops for late kettle aroma additions and stick to commercial hops for bittering. Mainly because the homegrown alpha acid level is harder to figure out.
