add the question

app/models/form/sales/pages/service_charge.rb

@@ -6,8 +6,8 @@ class Form::Sales::Pages::ServiceCharge < ::Form::Page
 
   def questions
     @questions ||= [
-      Form::Sales::Questions::HasServiceCharge.new(nil, nil, self),
-      Form::Sales::Questions::ServiceCharge.new(nil, nil, self),
+      Form::Sales::Questions::HasServiceCharge.new(nil, nil, self, staircasing: false),
+      Form::Sales::Questions::ServiceCharge.new(nil, nil, self, staircasing: false),
     ]
   end
 end

app/models/form/sales/pages/service_charge_staircasing.rb

@@ -0,0 +1,13 @@
+class Form::Sales::Pages::ServiceChargeStaircasing < ::Form::Page
+  def initialize(id, hsh, subsection)
+    super
+    @copy_key = "sales.sale_information.servicecharges"
+  end
+
+  def questions
+    @questions ||= [
+      Form::Sales::Questions::HasServiceCharge.new(nil, nil, self, staircasing: true),
+      Form::Sales::Questions::ServiceCharge.new(nil, nil, self, staircasing: true),
+    ]
+  end
+end

app/models/form/sales/questions/has_service_charge.rb

@@ -1,6 +1,6 @@
 class Form::Sales::Questions::HasServiceCharge < ::Form::Question
-  def initialize(id, hsh, subsection)
-    super
+  def initialize(id, hsh, subsection, staircasing:)
+    super(id, hsh, subsection)
     @id = "has_mscharge"
     @type = "radio"
     @answer_options = ANSWER_OPTIONS
@@ -15,7 +15,8 @@ class Form::Sales::Questions::HasServiceCharge < ::Form::Question
       ],
     }
     @copy_key = "sales.sale_information.servicecharges.has_servicecharge"
-    @question_number = QUESTION_NUMBER_FROM_YEAR[form.start_date.year] || QUESTION_NUMBER_FROM_YEAR[QUESTION_NUMBER_FROM_YEAR.keys.max]
+    @staircasing = staircasing
+    @question_number = question_number_from_year[form.start_date.year] || question_number_from_year[question_number_from_year.keys.max]
   end
 
   ANSWER_OPTIONS = {
@@ -23,5 +24,11 @@ class Form::Sales::Questions::HasServiceCharge < ::Form::Question
     "0" => { "value" => "No" },
   }.freeze
 
-  QUESTION_NUMBER_FROM_YEAR = { 2025 => 88 }.freeze
+  def question_number_from_year
+    if @staircasing
+      { 2026 => 0 }.freeze
+    else
+      { 2025 => 88 }.freeze
+    end
+  end
 end

app/models/form/sales/questions/service_charge.rb

@@ -1,16 +1,24 @@
 class Form::Sales::Questions::ServiceCharge < ::Form::Question
-  def initialize(id, hsh, subsection)
-    super
+  def initialize(id, hsh, subsection, staircasing:)
+    super(id, hsh, subsection)
     @id = "mscharge"
     @type = "numeric"
     @min = 1
+    @max = 9999.99
     @step = 0.01
     @width = 5
     @prefix = "£"
     @copy_key = "sales.sale_information.servicecharges.servicecharge"
-    @question_number = QUESTION_NUMBER_FROM_YEAR[form.start_date.year] || QUESTION_NUMBER_FROM_YEAR[QUESTION_NUMBER_FROM_YEAR.keys.max]
+    @staircasing = staircasing
+    @question_number = question_number_from_year[form.start_date.year] || question_number_from_year[question_number_from_year.keys.max]
     @strip_commas = true
   end
 
-  QUESTION_NUMBER_FROM_YEAR = { 2025 => 88 }.freeze
+  def question_number_from_year
+    if @staircasing
+      { 2026 => 0 }.freeze
+    else
+      { 2025 => 88 }.freeze
+    end
+  end
 end

app/models/form/sales/subsections/shared_ownership_staircasing_transaction.rb

@@ -25,6 +25,7 @@ class Form::Sales::Subsections::SharedOwnershipStaircasingTransaction < ::Form::
       Form::Sales::Pages::Mortgageused.new("staircase_mortgage_used_shared_ownership", nil, self, ownershipsch: 1),
       Form::Sales::Pages::MonthlyRentStaircasingOwned.new(nil, nil, self),
       Form::Sales::Pages::MonthlyRentStaircasing.new(nil, nil, self),
+      Form::Sales::Pages::ServiceChargeStaircasing.new("service_charge_staircasing", nil, self),
       Form::Sales::Pages::MonthlyChargesValueCheck.new("monthly_charges_shared_ownership_value_check", nil, self),
     ].compact
   end