diff --git a/src/specificClass.js b/src/specificClass.js
index 3e13de7..eb42032 100644
--- a/src/specificClass.js
+++ b/src/specificClass.js
@@ -124,12 +124,7 @@ class Reactor {
       return;
     }
 
-    let position;
-    if (measurementChild.config.functionality.distance !== 'undefined') {
-      position = measurementChild.config.functionality.distance;
-    } else {
-      position = measurementChild.config.functionality.positionVsParent;
-    }
+    const position = measurementChild.config.functionality.positionVsParent;
     const measurementType = measurementChild.config.asset.type;
     const eventName = `${measurementType}.measured.${position}`;
 
@@ -334,7 +329,7 @@ class Reactor_PFR extends Reactor {
   _updateMeasurement(measurementType, value, position, context) {
     switch(measurementType) {
       case "quantity (oxygen)":
-        let grid_pos = Math.round(position / this.config.length * this.n_x);
+        let grid_pos = Math.round(context.distance / this.config.length * this.n_x);
         this.state[grid_pos][S_O_INDEX] = value; // naive approach for reconciling measurements and simulation
         break;
       default: