Fix AddressPeriod(height) to align with halving heights

zip-0207.rst

@@ -86,14 +86,14 @@ block height is defined as follows::
     AddressChangeInterval = PostBlossomHalvingInterval / 48
     AddressPeriod(height) =
         floor((
-            height + AddressChangeInterval - SlowStartShift
+            height + PostBlossomHalvingInterval - HeightForHalving(1)
         ) / AddressChangeInterval)
     FundingStream[FUND].AddressIndex(height) =
         AddressPeriod(height) - AddressPeriod(FundingStream[FUND].StartHeight)
     Address(height) = FundingStream[FUND].Addresses[FundingStream[FUND].AddressIndex(height)]
 
 This has the property that all active funding streams change the address they are using on the same block
-height schedule, aligned to the end of the mining slow start so that 48 funding periods fit cleanly within a
+height schedule, aligned to the height of the first halving so that 48 funding periods fit cleanly within a
 halving interval. This can be leveraged to simplify implementations, by batching the necessary outputs for
 each funding period.
 
@@ -241,10 +241,12 @@ Example implementation
     {
         // Integer division is floor division in C++
         auto curPeriod = (
-            nHeight + params.nFundingPeriodLength - params.SubsidySlowStartShift()
+            nHeight + params.nSubsidyPostBlossomHalvingInterval - HeightForHalving(params, 1)
         ) / params.nFundingPeriodLength;
         auto startPeriod = (
-            params.vFundingPeriods[idx].startHeight + params.nFundingPeriodLength - params.SubsidySlowStartShift()
+            params.vFundingPeriods[idx].startHeight
+                + params.nSubsidyPostBlossomHalvingInterval
+                - HeightForHalving(params, 1)
         ) / params.nFundingPeriodLength;
         auto addressIndex = curPeriod - startPeriod;
         return params.vFundingPeriods[idx].addresses[addressIndex];