diff --git a/server/http_session_handler.go b/server/http_session_handler.go
index b83fb3a7d..49f6c6c8c 100644
--- a/server/http_session_handler.go
+++ b/server/http_session_handler.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"math"
 	"net/http"
 	"strconv"
 
@@ -50,9 +51,10 @@ func sessionHandler(w http.ResponseWriter, r *http.Request) {
 		if month != "" {
 			iMonth, err := strconv.Atoi(month)
 			if err != nil {
-				jsonError(w, http.StatusInternalServerError, err)
+				jsonError(w, http.StatusBadRequest, err)
 				return
 			}
+
 			fmtMonth = fmt.Sprintf("%02d", iMonth)
 			filename += "." + fmtMonth
 		}
@@ -64,6 +66,11 @@ func sessionHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// prepare data
+	for _, s := range res {
+		s.Odometer = math.Round(s.Odometer*10) / 10
+	}
+
 	if r.URL.Query().Get("format") == "csv" {
 		lang := r.URL.Query().Get("lang")
 		if lang == "" {