A bit of wordsmithing on help-scoring.md (dart-lang#8388)

doc/help-scoring.md

@@ -30,13 +30,13 @@ option.
 
 Pub.dev tracks and stores how many times each version of each package gets downloaded. This is used to display package usage metrics.
 
-The displayed download counts on pub.dev are aggregates based on raw server-side numbers counting the times a package archive has been downloaded.
+The displayed download counts on pub.dev are aggregates based on raw server-side numbers counting the times a package archive has been downloaded from the server.
 
-The download count is not a measure of how many users a package has. A package can have a high usage with low download counts because users may cache the package in their `PUB_CACHE`, which is a global cache. Hence, a particular package version will only be downloaded once per user, even if the user calls `pub get` many times across different projects.
+The download count is not a direct measure of how many users a package has. A package can have a high usage with relatively low download counts, because the pub client caches the downloads in the `PUB_CACHE`. This is a shared cache, so a particular package version will only be downloaded once per user on a particular developer machine, even if the user invokes `pub get` many times across different projects.
 
 On the other hand, for some packages the download count may be relatively high. For instance, the number can be high if the package is used as a dependency by other popular packages. The download counts can also be highly affected if the package is used by CI systems running tests, since these systems typically don't retain the `PUB_CACHE` between test runs.
 
-The download count is by no means a perfect metric, and should only be regarded as an indicator of popularity.
+The download count is not a perfect metric, and should only be regarded as an indicator of popularity.
 
 ## Popularity