blade size comparison SM Epic to Fenn 4

I've compared the blades of my Small-Mid Epic to my Fenn 4 in every way I can, i.e. measured, one on top of the other, etc., and they appear to be nearly the exact same size. The Fenn 4 blade is thicker but I can see no difference in surface area.
What am I missing as the Fenn 4 is supposed to be more similar to an Epic Large, isn't it?

My understanding is that the Fenn 4 is similar to the Bracsa 4. From the Fenn NZ website : "This is a Brasca shape with a teardrop shape. It has a very aggressive catch (the front part of the stroke) and is popular with sprinters. Size is medium."

The Epic Large is a monster blade designed specifically for sprint racers, and is far too big for surfski paddling.

Hi, Epic have 4 blade sizes, Small Mid, Mid, Mid Large and Large. As for the Fenn 4 I think it is a copy of either the Brasca 4 or the Epic Mid. You can`t keep up on the coppiers these days!