diff --git a/image_analysis/scale_merge/RfreeFlags.cpp b/image_analysis/scale_merge/RfreeFlags.cpp
index 05c33d9e1..0644d20f9 100644
--- a/image_analysis/scale_merge/RfreeFlags.cpp
+++ b/image_analysis/scale_merge/RfreeFlags.cpp
@@ -27,8 +27,8 @@ namespace {
     // twin laws (Le Page two-folds, with phenix.xtriage's default obliquity of 3 degrees, so a
     // pseudo-merohedral lattice counts as its higher metric; grouping too much only clusters the
     // free set, grouping too little splits twin mates). The centring is taken as P: the lattice of
-    // the cell's own basis vectors, the same whatever group a merge is in, so the merged file, the P1
-    // cross-check and any re-merge get one holohedry. On an R lattice in its hexagonal cell that is
+    // the cell's own basis vectors, the same whatever group a merge is in, so the merged file and any
+    // re-merge get one holohedry. On an R lattice in its hexagonal cell that is
     // 6/mmm rather than -3m, which groups each present reflection with exactly its -3m mates, the
     // extra ones being centring-absent. Empty when the cell does not carry the merging group itself
     // (a space group forced on a metric that does not have it): there is no holohedry to key on.
@@ -70,7 +70,7 @@ void AssignRfreeFlags(std::vector<MergedReflection> &merged, const gemmi::SpaceG
     // free reflection's twin mate in the working set almost every time (measured: 97-98% of the free
     // reflections that have a mate), and a twin-refined R-free then reads the working set through
     // I_calc. Keyed on the holohedry, twin mates share a flag, and the free set no longer depends on
-    // the space group a file is merged in - the merged MTZ, the P1 cross-check and a re-merge in any
+    // the space group a file is merged in - the merged MTZ and a re-merge in any
     // subgroup carry one free set (where the small-data floor below lifts the fraction differently in
     // two of them, the smaller set is contained in the larger: each orbit has one draw). As
     // phenix.refine does by default (use_lattice_symmetry).
diff --git a/image_analysis/scale_merge/RotationScaleMerge.h b/image_analysis/scale_merge/RotationScaleMerge.h
index bc72417f1..f3af5d8cb 100644
--- a/image_analysis/scale_merge/RotationScaleMerge.h
+++ b/image_analysis/scale_merge/RotationScaleMerge.h
@@ -135,13 +135,14 @@ public:
     //   compares nothing, asks for it to be left out.
     // group: the space group to merge in, for this Run only; null takes the experiment's. Given, the merge
     //   reads the experiment for nothing that changes during a run, so a caller may merge in its own group
-    //   (the P1 cross-check) on another thread while it goes on using the experiment.
+    //   (the finalist ledger's P1 merge) while the experiment's group is another.
     Result Run(bool for_search, bool full_stats, bool measure_cc_before_corrections,
                const gemmi::SpaceGroup *group = nullptr);
 
     // Whether Run() writes the per-frame G / CC / mosaicity back onto the outcomes (on by default). Off
-    // for a merge that is not the run's answer - the P1 cross-check - so the per-image table and the
-    // unmerged MTZ describe the merge that was written.
+    // for a merge that is not the run's answer - the quality guard's merge of the pre-pass frames, the
+    // finalist ledger's P1 merge - so the per-image table and the unmerged MTZ describe the merge that
+    // was written.
     void SetWriteBackPerFrameScale(bool on) { write_back_per_frame_scale = on; }
 
     // Merge only the first n frames of the outcomes (by default all of them). Set before Ingest().
diff --git a/image_analysis/scale_merge/SearchSpaceGroup.h b/image_analysis/scale_merge/SearchSpaceGroup.h
index b503cff73..06a28e213 100644
--- a/image_analysis/scale_merge/SearchSpaceGroup.h
+++ b/image_analysis/scale_merge/SearchSpaceGroup.h
@@ -451,7 +451,7 @@ struct SearchSpaceGroupOptions {
     //    The contrast has no pole: an unusually clean reference widens the denominator by a few per
     //    cent instead of shrinking the numerator's divisor towards zero.
     //
-    //    Calibrated over 149 rotation datasets with a known answer (the P1 cross-check merge of each,
+    //    Calibrated over 149 rotation datasets with a known answer (a P1 merge of each,
     //    read as the gate reads it - the mean over the operators a promotion ADDS): a genuine
     //    promotion reaches down to 0.77 and the worst false one on the corpus reads 0.695. That false
     //    one is a twinned monoclinic crystal whose 222 step adds the twin law (which is the