diff --git a/core/settings.rb b/core/settings.rb
index 70b3eccc..544ea748 100644
--- a/core/settings.rb
+++ b/core/settings.rb
@@ -36,7 +36,8 @@
     ['USERS_DEFAULT_LANG', "en_US", "Default locale for new users", 1, "str"],
     ['VCENTER_CPU_LIMIT_FREQ_PER_CORE', "{\"default\":2000}", "Frequency per Core limit for different Nodes(don't remove default)", 1, "object"],
     ['VCENTER_DRIVES_IOPS', "{\"HDD\":350,\"SSD\":1000}", "IOPs limits for Drive types", 1, "object"],
-    ['VNETS_TEMPLATES', "{}", "VNs Types to VNs Templates mapping(types must be upper case)", 1, "object"]
+    ['VNETS_TEMPLATES', "{}", "VNs Types to VNs Templates mapping(types must be upper case)", 1, "object"],
+    ['PRE_PAID_REDUCE_FACTOR', "{\"0\": 1}", "Reduce factor for Pre-Paid VMs depending on billing period", 1, "object"]
   ]
   required.each do | record |
     begin
diff --git a/lib/std++/main.rb b/lib/std++/main.rb
index dc9ce18b..7ac2a4e6 100644
--- a/lib/std++/main.rb
+++ b/lib/std++/main.rb
@@ -19,7 +19,7 @@ def debug_out
 
   # @!group Dev Tools
 
-  # Replaces string keys with symbol keys
+  # Replaces string keys with Symbol keys
   # @return [Hash]
   def to_sym!
     self.keys.each do |key|
@@ -28,7 +28,7 @@ def to_sym!
     self
   end
 
-  # Replaces all keys with string keys
+  # Replaces all keys with String keys
   # @return [Hash]
   def to_s!
     self.keys.each do |key|
@@ -37,6 +37,15 @@ def to_s!
     self
   end
 
+  # Converts all keys to Integer
+  # @return [Hash]
+  def keys_to_i!
+    self.keys.each do |key|
+      self[key.to_i] = self.delete key if key.class != Integer
+    end
+    self
+  end
+
   # Returns array of values with given keys
   # @param [Array] keys - Array of values
   # @return [Array]
diff --git a/service/objects/vm.rb b/service/objects/vm.rb
index 114ebdc4..11655f56 100644
--- a/service/objects/vm.rb
+++ b/service/objects/vm.rb
@@ -397,7 +397,8 @@ def calculate_showback stime_req, etime_req, _group_by_day = false
       }
     elsif bp.include? 'PRE' then
       curr = self['/VM/STIME'].to_i
-      delta = bp.split('_')[1].to_i * 86400
+      period = bp.split('_')[1].to_i
+      delta = period * 86400
 
       total = 0
 
@@ -412,10 +413,25 @@ def calculate_showback stime_req, etime_req, _group_by_day = false
         curr += delta
       end
 
+      reduce_factor = 1
+      reduce_factors = IONe::Settings['PRE_PAID_REDUCE_FACTOR'].keys_to_i!.sort.to_h
+
+      reduce_factors.each do | period_key, factor |
+        if period >= period_key then
+          reduce_factor = factor
+        else
+          break
+        end
+      end
+      reduce_factor = reduce_factor.to_f
+
       return {
         id: id, name: name,
-        TOTAL: total
+        total_billed: total, reduce_factor: reduce_factor,
+        TOTAL: total * reduce_factor
       }
+    else
+      raise ShowbackError, ["Unknown BILLING_PERIOD!", bp]
     end
   end
 
diff --git a/service/objects/vn.rb b/service/objects/vn.rb
index b650cf3e..6d5c0797 100644
--- a/service/objects/vn.rb
+++ b/service/objects/vn.rb
@@ -41,6 +41,8 @@ def ar_pool
     pool = to_hash['VNET']['AR_POOL']['AR']
     if pool.class == Hash then
       return [pool]
+    elsif pool.nil? then
+      return []
     else
       return pool
     end