Acid wash is a finish, not a dye. Each garment is treated individually, which is why no two pieces come out identical, and why the way you wash it changes how it ages.
Cold water, inside out
Turn the tee inside out before it goes in. Cold water keeps the contrast between the light and dark areas crisp; hot water flattens it into a uniform grey over time.
Skip the bleach, skip the softener
Bleach attacks the finish unevenly and leaves orange patches. Fabric softener coats the fibres and dulls the wash. Neither is doing you a favour.
Dry in shade
Direct sun will lift the darker areas faster than the lighter ones. Line dry in shade, or tumble on low. Iron warm on the reverse if you must.
Done this way, the wash settles into something better around month six, softer, with the contrast still intact.