diff --git a/src/commonMain/kotlin/uk/gov/hmrc/helptosavecalculator/FirstBonusTermCalculation.kt b/src/commonMain/kotlin/uk/gov/hmrc/helptosavecalculator/FirstBonusTermCalculation.kt
index 285e83b..cdda6d7 100644
--- a/src/commonMain/kotlin/uk/gov/hmrc/helptosavecalculator/FirstBonusTermCalculation.kt
+++ b/src/commonMain/kotlin/uk/gov/hmrc/helptosavecalculator/FirstBonusTermCalculation.kt
@@ -18,16 +18,16 @@ package uk.gov.hmrc.helptosavecalculator
 import uk.gov.hmrc.helptosavecalculator.models.FirstBonusInput
 import uk.gov.hmrc.helptosavecalculator.utils.monthsSince
 
-open class FirstBonusTermCalculation {
+internal class FirstBonusTermCalculation {
 
-    protected fun calculateTotalProjectedSavingsIncludeBonuses(
+    fun calculateTotalProjectedSavingsIncludeBonuses(
         totalProjectedSavings: Double,
         totalProjectedBonuses: Double
     ): Double {
         return totalProjectedSavings + totalProjectedBonuses
     }
 
-    protected fun calculateAdditionalSavingsThisMonth(input: FirstBonusInput): Double {
+    fun calculateAdditionalSavingsThisMonth(input: FirstBonusInput): Double {
         return if (input.regularPayment > input.paidInThisMonth) {
             input.regularPayment - input.paidInThisMonth
         } else {
@@ -35,7 +35,7 @@ open class FirstBonusTermCalculation {
         }
     }
 
-    protected fun calculateTotalProjectedSavings(
+    fun calculateTotalProjectedSavings(
         input: FirstBonusInput,
         additionalSavingsThisMonth: Double,
         monthsLeftInScheme: Int
@@ -43,14 +43,14 @@ open class FirstBonusTermCalculation {
         return input.currentBalance + additionalSavingsThisMonth + (input.regularPayment * monthsLeftInScheme)
     }
 
-    protected fun calculateTotalProjectedBonuses(
+    fun calculateTotalProjectedBonuses(
         projectedFirstBonus: Double,
         projectedFinalBonus: Double
     ): Double {
         return projectedFirstBonus + projectedFinalBonus
     }
 
-    protected fun calculateProjectedSavingsFirstBonusPeriod(
+    fun calculateProjectedSavingsFirstBonusPeriod(
         input: FirstBonusInput,
         additionalSavingsThisMonth: Double,
         monthsLeftInFirstTerm: Int
@@ -58,7 +58,7 @@ open class FirstBonusTermCalculation {
         return input.currentBalance + additionalSavingsThisMonth + (input.regularPayment * monthsLeftInFirstTerm)
     }
 
-    protected fun calculateHighestBalanceFirstBonusPeriod(
+    fun calculateHighestBalanceFirstBonusPeriod(
         input: FirstBonusInput,
         projectedSavingsFirstBonusPeriod: Double
     ): Double {
@@ -67,15 +67,15 @@ open class FirstBonusTermCalculation {
         } ?: projectedSavingsFirstBonusPeriod
     }
 
-    protected fun calculateProjectedFirstBonus(highestBalanceFirstBonusPeriod: Double): Double {
+    fun calculateProjectedFirstBonus(highestBalanceFirstBonusPeriod: Double): Double {
         return highestBalanceFirstBonusPeriod / 2
     }
 
-    protected fun calculateProjectedAdditionalSavingsFinalBonusPeriod(input: FirstBonusInput): Double {
+    fun calculateProjectedAdditionalSavingsFinalBonusPeriod(input: FirstBonusInput): Double {
         return input.regularPayment * 24
     }
 
-    protected fun calculateProjectedFinalBonus(
+    fun calculateProjectedFinalBonus(
         highestBalanceFinalBonusPeriod: Double,
         highestBalanceFirstBonusPeriod: Double
     ): Double {
@@ -86,7 +86,7 @@ open class FirstBonusTermCalculation {
         }
     }
 
-    protected fun calculateMonthsLeftInScheme(input: FirstBonusInput): Pair<Int, Int> {
+    fun calculateMonthsLeftInScheme(input: FirstBonusInput): Pair<Int, Int> {
         val startDate = input.accountStartDate.convertToDateTime()
         val secondTermEndDate = input.secondTermEndDate.convertToDateTime()
         val firstTermEndDate = input.firstTermEndDate.convertToDateTime()
diff --git a/src/commonMain/kotlin/uk/gov/hmrc/helptosavecalculator/FirstBonusTermCalculator.kt b/src/commonMain/kotlin/uk/gov/hmrc/helptosavecalculator/FirstBonusTermCalculator.kt
index f9790e2..471bfea 100644
--- a/src/commonMain/kotlin/uk/gov/hmrc/helptosavecalculator/FirstBonusTermCalculator.kt
+++ b/src/commonMain/kotlin/uk/gov/hmrc/helptosavecalculator/FirstBonusTermCalculator.kt
@@ -20,7 +20,9 @@ import uk.gov.hmrc.helptosavecalculator.models.FirstBonusCalculatorResponse
 import uk.gov.hmrc.helptosavecalculator.models.FirstBonusInput
 import uk.gov.hmrc.helptosavecalculator.validation.RegularPaymentValidators
 
-object FirstBonusTermCalculator : FirstBonusTermCalculation() {
+object FirstBonusTermCalculator {
+
+    private val calculation = FirstBonusTermCalculation()
 
     fun runFirstBonusCalculator(input: FirstBonusInput): FirstBonusCalculatorResponse {
         return calculateFirstBonus(input)
@@ -29,19 +31,25 @@ object FirstBonusTermCalculator : FirstBonusTermCalculation() {
     private fun calculateFirstBonus(input: FirstBonusInput): FirstBonusCalculatorResponse {
         validateUserInput(input.regularPayment)
 
-        val (monthLeftInScheme, monthLeftInFirstTerm) = calculateMonthsLeftInScheme(input)
-        val additionalSavingsThisMonth = calculateAdditionalSavingsThisMonth(input)
-        val totalProjectedSavings = calculateTotalProjectedSavings(input, additionalSavingsThisMonth, monthLeftInScheme)
-        val projectedSavingsFirstBonusPeriod = calculateProjectedSavingsFirstBonusPeriod(input,
+        val (monthLeftInScheme, monthLeftInFirstTerm) = calculation.calculateMonthsLeftInScheme(input)
+        val additionalSavingsThisMonth = calculation.calculateAdditionalSavingsThisMonth(input)
+        val totalProjectedSavings = calculation.calculateTotalProjectedSavings(input,
+                additionalSavingsThisMonth,
+                monthLeftInScheme)
+        val projectedSavingsFirstBonusPeriod = calculation.calculateProjectedSavingsFirstBonusPeriod(input,
                 additionalSavingsThisMonth,
                 monthLeftInFirstTerm)
-        val highestBalanceFirstBonusPeriod = calculateHighestBalanceFirstBonusPeriod(input,
+        val highestBalanceFirstBonusPeriod = calculation.calculateHighestBalanceFirstBonusPeriod(input,
                 projectedSavingsFirstBonusPeriod)
-        val projectedFirstBonus = calculateProjectedFirstBonus(highestBalanceFirstBonusPeriod)
-        val projectedAdditionalSavingsFinalBonusPeriod = calculateProjectedAdditionalSavingsFinalBonusPeriod(input)
-        val projectedFinalBonus = calculateProjectedFinalBonus(totalProjectedSavings, highestBalanceFirstBonusPeriod)
-        val totalProjectedBonuses = calculateTotalProjectedBonuses(projectedFirstBonus, projectedFinalBonus)
-        val totalProjectedSavingsIncludingBonuses = calculateTotalProjectedSavingsIncludeBonuses(totalProjectedSavings,
+        val projectedFirstBonus = calculation.calculateProjectedFirstBonus(highestBalanceFirstBonusPeriod)
+        val projectedAdditionalSavingsFinalBonusPeriod =
+                calculation.calculateProjectedAdditionalSavingsFinalBonusPeriod(input)
+        val projectedFinalBonus = calculation.calculateProjectedFinalBonus(totalProjectedSavings,
+                highestBalanceFirstBonusPeriod)
+        val totalProjectedBonuses = calculation.calculateTotalProjectedBonuses(projectedFirstBonus,
+                projectedFinalBonus)
+        val totalProjectedSavingsIncludingBonuses =
+                calculation.calculateTotalProjectedSavingsIncludeBonuses(totalProjectedSavings,
                 totalProjectedBonuses)
 
         return FirstBonusCalculatorResponse(