Low abv of spirit run

[M40685]

So I performed a stripping run from 75% down to 20%, after the stripping run I had to dilute a little over a gallon with 2 quarts of water to bring the abv down between 30 35%abv.
Running the spirit run I only got 25% max abv.
I’m curious what I may have done wrong, too much water etc?
I don’t want to make the same mistake again.
I’m using a pot still, mash is flaked maize and malted barley, no sugar added.
Thanks!