For tiny-window test DAOs (preprod_test: 30s), the prior anchor
(valid_from = starting_time, invalid_from = starting_time + 30)
gave zero past-side slack. With koios block_time vs real chain
clock skewing ±60s on the public endpoint, hitting that window
is essentially a coin flip — the tx submits but never confirms
because the next block lands after invalid_from.
Centering keeps the validator-required width unchanged but moves
valid_from to starting_time - 15, so the chain now has 15s of
past-side slack to land the tx in a block. Same width, same
in-script time check (starting_time still ∈ [valid_from, invalid_from)),
better landing odds.
Sulkta-shape DAOs (1800s windows) are unaffected: 900s of slack
each side is plenty either way.