diff --git a/LuaLibs/LeadInOutLib.lua b/LuaLibs/LeadInOutLib.lua
index d9f9d86..a2ed766 100644
--- a/LuaLibs/LeadInOutLib.lua
+++ b/LuaLibs/LeadInOutLib.lua
@@ -219,7 +219,7 @@ function LeadInOutLib.CalculateLeadInOut( sLeadInOutType, Parameters, OptionalPa
    elseif sLeadInOutType == 'SpecialTangent' then
 
       -- uscita con componente aggiuntiva perpendicolare
-      LeadIn.nType = MCH_MILL_LO.PERP_TG
+      LeadOut.nType = MCH_MILL_LO.PERP_TG
       local dStartEndOffset = 10
       local ptEndAtDepthWithOffset = ptEndAtDepth + Edge.vtN * dStartEndOffset
       local ptEndBladeCenterWithOffset = ptEndBladeCenter + Edge.vtN * dStartEndOffset
@@ -277,6 +277,8 @@ function LeadInOutLib.InvertLeadInOut( LeadIn, LeadOut)
 
    local dOriginalStartAddLength = LeadIn.dStartAddLength
    local dOriginalEndAddLength = LeadOut.dEndAddLength
+   local nOriginalLeadInType = LeadIn.nType
+   local nOriginalLeadOutType = LeadOut.nType
 
    LeadIn, LeadOut = LeadOut, LeadIn
 
@@ -284,6 +286,12 @@ function LeadInOutLib.InvertLeadInOut( LeadIn, LeadOut)
    LeadOut.dEndAddLength = dOriginalStartAddLength
    LeadIn.dEndAddLength = nil
    LeadOut.dStartAddLength = nil
+   if nOriginalLeadInType == MCH_MILL_LI.TG_PERP then
+      LeadOut.nType = MCH_MILL_LO.PERP_TG
+   end
+   if nOriginalLeadOutType == MCH_MILL_LO.PERP_TG then
+      LeadIn.nType = MCH_MILL_LI.TG_PERP
+   end
 
    return LeadIn, LeadOut
 end