diff --git a/LuaLibs/ProcessDrill.lua b/LuaLibs/ProcessDrill.lua
index 1422d55..adaf08c 100644
--- a/LuaLibs/ProcessDrill.lua
+++ b/LuaLibs/ProcessDrill.lua
@@ -711,7 +711,7 @@ function ProcessDrill.Make( Proc, nPhase, nRawId, nPartId)
             ProcLastStep.Id = idProcLastStep
             ProcLastStep.Flg = 1
             ProcLastStep.Double = 0
-            ProcLastStep.dCustomMaxElev = dDepth
+            ProcLastStep.dCustomMaxElev = dLastStepDepth - dDepth
             local bOkLastStep, sWarnLastStep = ProcessDrill.Make( ProcLastStep, nPhase, nRawId, nPartId)
             if not bOkLastStep then
                sWarnLastStep = 'Drillpocket double : incomplete, last step missing'