diff --git a/Tools/TimePlot.hs b/Tools/TimePlot.hs
--- a/Tools/TimePlot.hs
+++ b/Tools/TimePlot.hs
@@ -594,7 +594,7 @@
       bin@(t1,t2) <- getBin
       states <- getStates
       let binSizeSec = toSeconds (t2 `sub` t1) t1
-      RWS.tell [(bin, [(s, (fromIntegral npulse/binSizeSec + area + toSeconds (t2 `sub` start) t2*nopen)/binSizeSec) | (s,(area,start,nopen,npulse)) <- states])]
+      RWS.tell [(bin, [(s, (fromIntegral npulse + area + toSeconds (t2 `sub` start) t2*nopen)/binSizeSec) | (s,(area,start,nopen,npulse)) <- states])]
       forM_ states $ \(s, (area,start,nopen,_)) -> putState s (0,t2,nopen,0)
       nextBin
 
@@ -607,9 +607,9 @@
                else step'' ev
     step'' ev@(t,s,e) = do (t1,t2) <- getBin; when (t < t1 || t >= t2) (error "Outside bin"); step' ev
     step' (t, s, SetTo _) = modState s t id
-    step' (t, s, Pulse _) = modState s t id
-    step' (t, s, Rise)    = modState s t $ \(area, start, nopen, npulse) -> (area+toSeconds (t `sub` start) t*nopen, t, nopen+1, npulse)
-    step' (t, s, Fall)    = modState s t $ \(area, start, nopen, npulse) -> (area+toSeconds (t `sub` start) t*nopen, t, nopen-1, npulse)
+    step' (t, s, Pulse _) = modState s t $ \(area, start, nopen, npulse) -> (area,                                   start, nopen,   npulse+1)
+    step' (t, s, Rise)    = modState s t $ \(area, start, nopen, npulse) -> (area+toSeconds (t `sub` start) t*nopen, t,     nopen+1, npulse)
+    step' (t, s, Fall)    = modState s t $ \(area, start, nopen, npulse) -> (area+toSeconds (t `sub` start) t*nopen, t,     nopen-1, npulse)
     flush                 = getBin >>= \(t1,t2) -> when (t2 <= maxTime) (flushBin >> flush)
 
 values2timeBins :: (Ord t) => [t] -> [(t,a)] -> [[a]]
@@ -747,7 +747,7 @@
   "     and finishing tasks on different machines, and you want to plot a diagram",
   "     showing the number of utilized machines and how this number is composed of",
   "     utilization by different jobs, make your trace say '>job-JOBID'...'<job-JOBID'",
-  "     and use -k job 'within[-] count 1'.",
+  "     and use -k job 'within[-] acount 1'.",
   "     Explanation: if you specify -k REGEX 'within[.] SOMETHING', timeplot will",
   "     take all tracks matching REGEX, split each track around the first '.', giving",
   "     a 'supertrack' and 'subtrack' (e.g. customer.John -> customer, John), ",
@@ -756,8 +756,8 @@
   "     events, e.g. 'lines' will simply draw several line plots, one per subtrack.",
   "  'acount N' is for activity counts: a histogram is drawn with granularity",
   "     of N time units, where the bin corresponding to [t..t+N) has value",
-  "     'what was the average number of active events or impulses in that",
-  "     interval'. When used inside 'within', the histogram is a stacked one,",
+  "     'what was the average number of active events or impulses per time unit ",
+  "     within that interval'. When used inside 'within', the histogram is a stacked one,",
   "     with one vertical bar per subtrack in each bin.",
   "  'apercent N B' is for activity percentages of a basis: like 'acount N',",
   "     but instead of X you get 100*X/B",
diff --git a/timeplot.cabal b/timeplot.cabal
--- a/timeplot.cabal
+++ b/timeplot.cabal
@@ -1,5 +1,5 @@
 name: timeplot
-version: 0.3.6
+version: 0.3.7
 cabal-version: >=1.6
 build-type: Simple
 license: BSD3