-- Increase expected_value precision from numeric(10,2) to numeric(10,4)
-- numeric(10,2) rounds each participant's EV to 2dp; across 20 drivers the
-- accumulated rounding can exceed 0.05, pushing the total above 340.
-- numeric(10,4) limits per-participant error to ±0.00005 (total <0.001).

ALTER TABLE "participants"
  ALTER COLUMN "expected_value" TYPE numeric(10,4) USING expected_value::numeric(10,4);

ALTER TABLE "participant_expected_values"
  ALTER COLUMN "expected_value" TYPE numeric(10,4) USING expected_value::numeric(10,4);

ALTER TABLE "participant_ev_snapshots"
  ALTER COLUMN "calculated_ev" TYPE numeric(10,4) USING calculated_ev::numeric(10,4);