diff --git a/yandexmarket/products.proto b/yandexmarket/products.proto
index 979774d..a72a40a 100644
--- a/yandexmarket/products.proto
+++ b/yandexmarket/products.proto
@@ -26,7 +26,8 @@ message CalculateProductTariffsRequest {
   }
 
   int64 marketplace_id = 1;
-  repeated Offers offers = 2;
+  Parameters parameters = 2;
+  repeated Offers offers = 3;
 }
 
 message CalculateProductTariffsResponse {
@@ -41,21 +42,21 @@ message CalculateProductTariffsResponse {
     int64 quantity = 7;
   }
 
-  message Parameters {
+  message Parameter {
     string name = 1;
     string value = 2;
   }
 
-  message Tariffs {
+  message Tariff {
     string type = 1;
     int64 amount = 2;
     string currency = 3;
-    repeated Parameters parameters = 4;
+    repeated Parameter parameters = 4;
   }
 
   message Offers {
     Offer offer = 1;
-    repeated Tariffs tariffs = 2;
+    repeated Tariff tariffs = 2;
   }
 
   repeated Offers offers = 1;