All Blue Potato Questions

[TechGuy]

I planted these for the first time mid April. When I cut up my seed potatoes the inside was dark rich blue. When harvesting this year, there is only slight blue color. Its more spotty than solid. What imight be happening to not develop the blue flesh color?

On another note, I have pretty sandy soil. I have had irregular rain. The skin is rather rough- almost flaky or slight cracking. Would this be caused from letting the soil dry out too much?

They have been in the ground close to 100 days and plants are definitely browning and looking done.