Added in ability to manually adjust the gcode time multiplier

StaticData/SliceSettings/Layouts.txt

@@ -191,6 +191,7 @@ Printer
         max_acceleration
         max_velocity
         jerk_velocity
+        print_time_estimate_multiplier
     Slicing
       Slicing Options
         output_only_first_layer

StaticData/SliceSettings/Properties.json

@@ -1905,6 +1905,15 @@
     "Units": "mm/s",
     "RebuildGCodeOnChange": false
   },
+  {
+    "SlicerConfigName": "print_time_estimate_multiplier",
+    "PresentationName": "Time Multiplier",
+    "HelpText": "Adjust this to correct differences between expected printing speeds and actual printing speeds.",
+    "DataEditType": "POSITIVE_DOUBLE",
+    "Units": "%",
+    "ShowIfSet": "!sla_printer",
+    "DefaultValue": "100"
+  },
   {
     "SlicerConfigName": "manual_movement_speeds",
     "PresentationName": "Manual Movement Speeds",