_nextDraw(_nextNumberOfTiers, uint96(_contributionsForDraw(lastClosedDrawId + 1)));
(SD59x18 _vaultPortion, SD59x18 _tierOdds, uint16 _drawDuration) = _computeVaultTierDetails(
      msg.sender,
      _tier,
      numberOfTiers,
      lastClosedDrawId
    );
vaultPortion = _getVaultPortion(
      _vault,
      uint16(drawDuration > _lastClosedDrawId ? 0 : _lastClosedDrawId - drawDuration + 1),
      _lastClosedDrawId + 1,
      smoothing.intoSD59x18()
    );
diff --git a/src/PrizePool.sol b/src/PrizePool.sol
index a42a27e..34548c9 100644
--- a/src/PrizePool.sol
+++ b/src/PrizePool.sol
@@ -902,8 +902,8 @@ contract PrizePool is TieredLiquidityDistributor {
     drawDuration = uint16(TierCalculationLib.estimatePrizeFrequencyInDraws(tierOdds));
     vaultPortion = _getVaultPortion(
       _vault,
-      uint16(drawDuration > _lastClosedDrawId ? 0 : _lastClosedDrawId - drawDuration + 1),
-      _lastClosedDrawId + 1,
+      uint16(drawDuration > _lastClosedDrawId ? 0 : _lastClosedDrawId - drawDuration),
+      _lastClosedDrawId,
       smoothing.intoSD59x18()
     );
   }
