diff --git a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelateNG.java b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelateNG.java
index 977fd75637..fa3ee65696 100644
--- a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelateNG.java
+++ b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelateNG.java
@@ -320,7 +320,11 @@ private void computeAtPoints(RelateGeometry geom, boolean isA,
      * if it has areas OR if the predicate requires checking for 
      * exterior interaction.
      * In particular, this avoids testing line ends against lines 
-     * for the intersects predicate. 
+     * for the intersects predicate (since these are checked
+     * during segment/segment intersection checking anyway). 
+     * Checking points against areas is necessary, since the input
+     * linework may be entirely disjoint if one input lies wholly 
+     * inside an area.
      */
     boolean checkDisjointPoints = geomTarget.hasDimension(Dimension.A) 
         || topoComputer.isExteriorCheckRequired(isA);
diff --git a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/TopologyPredicate.java b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/TopologyPredicate.java
index 639427ede9..53f7750f20 100644
--- a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/TopologyPredicate.java
+++ b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/TopologyPredicate.java
@@ -52,9 +52,13 @@ default boolean requiresSelfNoding() {
   /**
    * Reports whether this predicate requires checking if the source input intersects
    * the Exterior of the target input.
-   * This allows some performance optimizations if not required.
+   * This is the case if:
+   * <pre>
+   * IM[Int(Src), Ext(Tgt)] >= 0 or IM[Bdy(Src), Ext(Tgt)] >= 0
+   * </pre> 
+   * When not required to evaluate a predicate this permits performance optimization.
    *  
-   * @param isSourceA
+   * @param isSourceA flag indicating which input geometry is the source
    * @return true if the predicate requires checking whether the source intersects the target exterior
    */
   default boolean requiresExteriorCheck(boolean isSourceA) {