diff --git a/Doc/UserManual/Multilayers.tex b/Doc/UserManual/Multilayers.tex
index eef41afcdcd6667a3a46bc804815652da2064457..40724f54eed800d2dc82241ca3269b83b81b5305 100644
--- a/Doc/UserManual/Multilayers.tex
+++ b/Doc/UserManual/Multilayers.tex
@@ -327,9 +327,10 @@ radiation from below or above is totally reflected at its boundaries.
 In \BornAgain,
 such total reflection is imposed if $|f_l|$ falls below a very small value
 (currently $10^{-20}$).
-However, this has hardly any practical importance
-because except in vacuum the index of refraction always
-as an absorptive component that prevents $f_l$ from becoming zero.
+However, except for the top vacuum layer
+this ought to be inconsequential
+because the index of refraction should always
+have an absorptive component that prevents $f_l$ from becoming zero.
 
 
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