diff --git a/cardano-api/gen/Test/Gen/Cardano/Api/Typed.hs b/cardano-api/gen/Test/Gen/Cardano/Api/Typed.hs
index 643d570cc1..0dea0ee6ac 100644
--- a/cardano-api/gen/Test/Gen/Cardano/Api/Typed.hs
+++ b/cardano-api/gen/Test/Gen/Cardano/Api/Typed.hs
@@ -626,9 +626,8 @@ genTxUpdateProposal sbe =
 
 genTxMintValue :: CardanoEra era -> Gen (TxMintValue BuildTx era)
 genTxMintValue =
-  caseByronOrShelleyToAllegraOrMaryEraOnwards
-    (const (pure TxMintNone))
-    (const (pure TxMintNone))
+  inEonForEra
+    (pure TxMintNone)
     (\supported ->
       Gen.choice
         [ pure TxMintNone
diff --git a/cardano-api/internal/Cardano/Api/Eras.hs b/cardano-api/internal/Cardano/Api/Eras.hs
index bf13a50240..b9b8bfabef 100644
--- a/cardano-api/internal/Cardano/Api/Eras.hs
+++ b/cardano-api/internal/Cardano/Api/Eras.hs
@@ -42,7 +42,6 @@ module Cardano.Api.Eras
   , caseByronOrShelleyBasedEra
 
     -- ** Case on ShelleyBasedEra
-  , caseByronOrShelleyToAllegraOrMaryEraOnwards
   , caseByronToAlonzoOrBabbageEraOnwards
   , caseShelleyToAllegraOrMaryEraOnwards
   , caseShelleyToMaryOrAlonzoEraOnwards
diff --git a/cardano-api/internal/Cardano/Api/Eras/Case.hs b/cardano-api/internal/Cardano/Api/Eras/Case.hs
index 6c18b37d39..202315da7c 100644
--- a/cardano-api/internal/Cardano/Api/Eras/Case.hs
+++ b/cardano-api/internal/Cardano/Api/Eras/Case.hs
@@ -7,7 +7,6 @@
 module Cardano.Api.Eras.Case
   ( -- Case on CardanoEra
     caseByronOrShelleyBasedEra
-  , caseByronOrShelleyToAllegraOrMaryEraOnwards
   , caseByronToAlonzoOrBabbageEraOnwards
 
     -- Case on ShelleyBasedEra
@@ -58,23 +57,6 @@ caseByronOrShelleyBasedEra l r = \case
   BabbageEra -> r ShelleyBasedEraBabbage
   ConwayEra  -> r ShelleyBasedEraConway
 
--- | @caseByronOrShelleyToAllegraOrMaryEraOnwards l m r era@ applies @l@ to byron; @m@ to shelley, and allegra;
--- and @r@ to mary and later eras.
-caseByronOrShelleyToAllegraOrMaryEraOnwards :: ()
-  => (ByronEraOnlyConstraints era => ByronEraOnly era -> a)
-  -> (ShelleyToAllegraEraConstraints era => ShelleyToAllegraEra era -> a)
-  -> (MaryEraOnwardsConstraints era => MaryEraOnwards era -> a)
-  -> CardanoEra era
-  -> a
-caseByronOrShelleyToAllegraOrMaryEraOnwards l m r = \case
-  ByronEra   -> l ByronEraOnlyByron
-  ShelleyEra -> m ShelleyToAllegraEraShelley
-  AllegraEra -> m ShelleyToAllegraEraAllegra
-  MaryEra    -> r MaryEraOnwardsMary
-  AlonzoEra  -> r MaryEraOnwardsAlonzo
-  BabbageEra -> r MaryEraOnwardsBabbage
-  ConwayEra  -> r MaryEraOnwardsConway
-
 -- | @caseByronToAlonzoOrBabbageEraOnwards f g era@ applies @f@ to byron, shelley, allegra, mary, and alonzo;
 -- and @g@ to babbage and later eras.
 caseByronToAlonzoOrBabbageEraOnwards :: ()
diff --git a/cardano-api/internal/Cardano/Api/Fees.hs b/cardano-api/internal/Cardano/Api/Fees.hs
index 43eea7906b..cc2edd6913 100644
--- a/cardano-api/internal/Cardano/Api/Fees.hs
+++ b/cardano-api/internal/Cardano/Api/Fees.hs
@@ -49,6 +49,7 @@ import           Cardano.Api.Address
 import           Cardano.Api.Certificate
 import           Cardano.Api.Eon.BabbageEraOnwards
 import           Cardano.Api.Eon.ByronEraOnly
+import           Cardano.Api.Eon.MaryEraOnwards
 import           Cardano.Api.Eon.ShelleyBasedEra
 import           Cardano.Api.Eras.Case
 import           Cardano.Api.Eras.Core
@@ -821,11 +822,11 @@ makeTransactionBodyAutoBalance sbe systemstart history lpp@(LedgerProtocolParame
           ]
 
     let maxLovelace = Lovelace (2^(64 :: Integer)) - 1
-    let changeTxOut = caseByronOrShelleyToAllegraOrMaryEraOnwards
-          (const $ lovelaceToTxOutValue era maxLovelace)
-          (const $ lovelaceToTxOutValue era maxLovelace)
-          (const $ TxOutValueShelleyBased sbe (nonAdaChange & A.adaAssetL sbe .~ lovelaceToCoin maxLovelace))
-          era
+    let changeTxOut = forShelleyBasedEraInEon sbe
+          (lovelaceToTxOutValue era maxLovelace)
+          (\w -> maryEraOnwardsConstraints w
+            $ TxOutValueShelleyBased sbe (nonAdaChange & A.adaAssetL sbe .~ lovelaceToCoin maxLovelace)
+          )
 
     let (dummyCollRet, dummyTotColl) = maybeDummyTotalCollAndCollReturnOutput txbodycontent changeaddr
     txbody1 <- first TxBodyError $ -- TODO: impossible to fail now
diff --git a/cardano-api/src/Cardano/Api.hs b/cardano-api/src/Cardano/Api.hs
index c35637189a..2071f2188f 100644
--- a/cardano-api/src/Cardano/Api.hs
+++ b/cardano-api/src/Cardano/Api.hs
@@ -132,7 +132,6 @@ module Cardano.Api (
 
     -- ** Case on CardanoEra
     caseByronOrShelleyBasedEra,
-    caseByronOrShelleyToAllegraOrMaryEraOnwards,
     caseByronToAlonzoOrBabbageEraOnwards,
 
     -- ** Case on ShelleyBasedEra