diff --git a/csaxs_bec/bec_ipython_client/plugins/omny/AI_docs/TODO_fermat_asymmetry_port.md b/csaxs_bec/bec_ipython_client/plugins/omny/AI_docs/TODO_fermat_asymmetry_port.md
index dd5684e4..140f989b 100644
--- a/csaxs_bec/bec_ipython_client/plugins/omny/AI_docs/TODO_fermat_asymmetry_port.md
+++ b/csaxs_bec/bec_ipython_client/plugins/omny/AI_docs/TODO_fermat_asymmetry_port.md
@@ -13,6 +13,18 @@ symmetric, keeps x spacing fixed at `step` and scales y spacing by the ratio
 while preserving the requested FOV. Soft-clamped to `[0.1, 10]` (with a
 `logger.warning` when clamped), same style as `zshift`/`corridor_size`.
 
+**Effective spacing (verified against generated data, see
+`docs/plans/flomni-fermat-asymmetry.md`'s conversation for the measurement
+method):** x spacing always stays at `step`; y spacing becomes `step /
+fermat_asymmetry`. E.g. with `step=1 um`, `fovx=fovy=10 um`: `fermat_asymmetry=0.7`
+-> x spacing 1.0 um, y spacing ~1.43 um (sparser), ~70 points;
+`fermat_asymmetry=1.3` -> x spacing 1.0 um, y spacing ~0.77 um (denser),
+~130 points. Point count scales with the ratio since the FOV is fixed but
+the density isn't. Same relationship should be documented for OMNY once
+ported (Flomni's user doc has this table -- see
+`docs/user/ptychography/flomni.md`, "Effective spacing with
+`fermat_asymmetry`" -- OMNY's equivalent doc, if any, should get the same).
+
 ## Important: compose with the already-ported sub-step randomization
 
 Before this, `fixes/flomni_beamtime_2` already ported a *different* fix to
diff --git a/docs/user/ptychography/flomni.md b/docs/user/ptychography/flomni.md
index 4bc4fba7..932cf613 100644
--- a/docs/user/ptychography/flomni.md
+++ b/docs/user/ptychography/flomni.md
@@ -234,6 +234,18 @@ The basic scan function can be called by `scans.flomni_fermat_scan()` and offers
 Example:  
 `scans.flomni_fermat_scan(fovx=10, fovy=10, cenx=0, ceny=0, step=1, fermat_asymmetry=1.0, zshift=0, angle=0, exp_time=0.1, frames_per_trigger=1, burst_at_each_point=1)`
 
+**Effective spacing with `fermat_asymmetry`:** the x spacing always stays at `step`;
+the y spacing becomes `step / fermat_asymmetry`. So with `step=1 um`:
+
+| fermat_asymmetry | x spacing | y spacing | points (fovx=fovy=10 um example) |
+| --- | --- | --- | --- |
+| 0.7 | 1.0 um | ~1.43 um (sparser) | ~70 |
+| 1.0 (default) | 1.0 um | 1.0 um | ~100 |
+| 1.3 | 1.0 um | ~0.77 um (denser) | ~130 |
+
+The requested FOV stays exactly as specified either way -- only the point density
+(and therefore the point count and scan duration) changes.
+
 The Fermat spiral's sub-step phase is also randomized on every projection (drawn
 fresh per scan, not user-configurable) to decorrelate position-tied reconstruction
 errors that would otherwise accumulate into ring artifacts across a tomographic