Me personally I would not have decrease the daily dosage by so much, more like 8mg daily which is a 14mg (-98mg per week) reduction that can have BIG impacts on hormone levels.
Now if you're going to stick with this protocol, stick with it for at least 6 weeks. As for whether or not the dosage of anastrozole can greatly affect estradiol levels, the whole point to daily dosing is so that you can drop the AI altogether.
My estradiol is crushed at any dosage of anastrozole, even 1/8 of a 0.050 dose.