I haven't done a CWE in a while, as my tolerance doesn't permit it to be worthwhile with any sensible amount of tablets anymore. But when I used to, I always found that stirring them vigorously for that extra minute or two made a huge difference in potency.
Not saying your method is bollocks or anything shammy, as you know I have nothing but

for you.
Maybe it's something to do with my method that doesn't allow such a procedure as pouring the water over the powder to be effective? I certainly wish it worked for me like that though...
My Method
1. Chill 200ml water in freezer to get it fucking cold. With my old freezer it took about 10 minutes for ice to appear, the one where I am now takes about 20, I try to take it out before this happens.
2. 32 tabs in one glass, the other 32 in another glass, all ground up nicely with my grinder. Add 100ml water to each and stir vigorously for 4-5 minutes for each glass. [If I'm using tabs which dissolve easily, instead of grinding them... I'll add the water, leave them in the fridge for 5 mins and then stir for 2 mins. Seems to work out about the same.]
3. Wet an old work shirt and set it up over two pint glasses, add the solutions and give it around 15 mins (until the liquid has become sludge).
4. Pepare another pint glass with a wet coffee filter and put it to one side. Gently(!) and one at a time, squeeze the two 'parcels' of CWE into their respective glasses (the ones they are dripping into) until it starts to run cloudy and then move the parcels over to the new empty glass, and squeeze the rest into the coffee filter.