diff --git a/.circleci/env.sh b/.circleci/env.sh
index 6543b62b2de..1e997f97173 100755
--- a/.circleci/env.sh
+++ b/.circleci/env.sh
@@ -85,7 +85,6 @@ echo "export PROJECT_ROOT=\"${PROJECT_ROOT}\";" >> $bazelVarEnv
 echo "export CI_BRANCH=\"${CI_BRANCH}\";" >> $bazelVarEnv
 echo "export CI_BUILD_URL=\"${CI_BUILD_URL}\";" >> $bazelVarEnv
 echo "export CI_COMMIT=\"${CI_COMMIT}\";" >> $bazelVarEnv
-echo "export CI_COMMIT_RANGE=\"${CI_COMMIT_RANGE}\";" >> $bazelVarEnv
 echo "export CI_PULL_REQUEST=\"${CI_PULL_REQUEST}\";" >> $bazelVarEnv
 echo "export CI_REPO_NAME=\"${CI_REPO_NAME}\";" >> $bazelVarEnv
 echo "export CI_REPO_OWNER=\"${CI_REPO_OWNER}\";" >> $bazelVarEnv
diff --git a/scripts/ci/payload-size.js b/scripts/ci/payload-size.js
index 90f8da78399..0f2eaf2ced4 100644
--- a/scripts/ci/payload-size.js
+++ b/scripts/ci/payload-size.js
@@ -13,12 +13,15 @@ const fs = require('fs');
 const path = require('path');
 
 // Get branch and project name from command line arguments.
-const [, , limitFile, project, branch, commit] = process.argv;
+const [, , limitFile, project, commit] = process.argv;
 
 // Load sizes.
 const currentSizes = JSON.parse(fs.readFileSync('/tmp/current.log', 'utf8'));
 const allLimitSizes = JSON.parse(fs.readFileSync(limitFile, 'utf8'));
-const limitSizes = allLimitSizes[project][branch] || allLimitSizes[project]['master'];
+
+// TODO: Change the `master` golden key to something more obvious, or remove it. The branch
+// name is unreasonable since the limits are always taken from the currently checked-out revision.
+const limitSizes = allLimitSizes[project]['master'];
 
 // Check current sizes against limits.
 let failed = false;
diff --git a/scripts/ci/payload-size.sh b/scripts/ci/payload-size.sh
index f036834c63b..496d0acdfdb 100644
--- a/scripts/ci/payload-size.sh
+++ b/scripts/ci/payload-size.sh
@@ -66,9 +66,8 @@ checkSize() {
   name="$1"
   limitFile="$2"
 
-  # In non-PR builds, `CI_BRANCH` is the branch being built (e.g. `pull/12345`), not the targeted branch.
-  # Thus, PRs will fall back to using the size limits for `master`.
-  node ${PROJECT_ROOT}/scripts/ci/payload-size.js $limitFile $name ${CI_BRANCH:-} ${CI_COMMIT:-}
+  # PRs and non-PR pushes will always test against the size-limits of the current revision.
+  node ${PROJECT_ROOT}/scripts/ci/payload-size.js $limitFile $name ${CI_COMMIT:-}
 }
 
 # Write timestamp to global variable `$payloadData`.
@@ -87,15 +86,10 @@ addBuildUrl() {
   payloadData="$payloadData\"buildUrl\": \"$buildUrl\", "
 }
 
-# Write the commit message for the current CI commit range to global variable `$payloadData`.
-#   $1: string - The commit range for this build (in `<SHA-1>...<SHA-2>` format).
+# Write the commit message for the specified CI commit to global variable `$payloadData`.
+#   $1: string - The commit SHA for this build (in `<SHA-1>` format).
 addMessage() {
-  commitRange="$1"
-
-  # Grab the set of SHAs for the message. This can fail when you force push or do initial build
-  # because $CI_COMMIT_RANGE may contain the previous SHA which will not be in the
-  # force push or commit, hence we default to last commit.
-  message=$(git --git-dir ${PROJECT_ROOT}/.git log --oneline $commitRange -- || git --git-dir ${PROJECT_ROOT}/.git log --oneline -n1)
+  message="${1}"
   message=$(echo $message | sed 's/\r//g' | sed 's/\\/\\\\/g' | sed 's/"/\\"/g')
   payloadData="$payloadData\"message\": \"$message\", "
 }
@@ -147,7 +141,7 @@ trackPayloadSize() {
     echo "Uploading data for '$name'..."
     addTimestamp
     addBuildUrl $CI_BUILD_URL
-    addMessage $CI_COMMIT_RANGE
+    addMessage $CI_COMMIT
     uploadData $name
   else
     echo "Skipped uploading data for '$name', because this is a pull request."