diff --git a/src/ClockParser.jl b/src/ClockParser.jl
index 70ba75c..0bf0c7c 100644
--- a/src/ClockParser.jl
+++ b/src/ClockParser.jl
@@ -100,10 +100,12 @@ function get_skew_and_riseup(file::T) where {T <: AbstractString}
     skew = missing
     is_raised = false
 
-    let
-        _time, high = _parse_line(popfirst!(lines))
+    last_low_time = let
+        time, high = _parse_line(popfirst!(lines))
         if high == 0
-            last_low_time = time
+            time
+        else
+            missing
         end
     end