adding a third receive pin to Arduino cap sense sketch problems.

hello basically trying to add a third receive pin (with a view to add an additional 3 , six in total) to the sketch that you download with the arduino capsense library. I tried using a common receive pin but it didn’t work in the context of my project.

this works fine

#include <CapacitiveSensor.h>

boolean check1 = false;
boolean check2 = false;

/*
 * CapitiveSense Library Demo Sketch
 * Paul Badger 2008
 * Uses a high value resistor e.g. 10M between send pin and receive pin
 * Resistor effects sensitivity, experiment with values, 50K - 50M. Larger resistor values yield larger sensor values.
 * Receive pin is the sensor pin - try different amounts of foil/metal on this pin
 */


CapacitiveSensor   cs_7_6 = CapacitiveSensor(7,6);  
CapacitiveSensor   cs_2_4 = CapacitiveSensor(2,4);// 10M resistor between pins 4 & 2, pin 2 is sensor pin, add a wire and or foil if desired
       // 10M resistor between pins 4 & 8, pin 8 is sensor pin, add a wire and or foil





void setup()                    
{

Serial.begin (9600);
}
void loop()                    
{
    long start = millis();
    long total1 =  cs_7_6.capacitiveSensor(30);
  long total2 =  cs_2_4.capacitiveSensor(30);

    Serial.print(millis() - start);        // check on performance in milliseconds
    Serial.println("\t");                    // tab character for debug windown spacing

               // print sensor output 3

Serial.println (total2);
Serial.println (total1);
    delay(25);                             // arbitrary delay to limit data to serial port 



  if (total1 >100)  {   // you can change this parameter to fine tune the sensitivity
    if (!check1){         
      Keyboard.press(KEY_CAPS_LOCK);
       Keyboard.press ('f');     
     check1 = !check1;   
    }         
  }
  if (total1 <95) {     
    if (check1){ 
      Keyboard.release ('f'); 
      check1 = !check1;   
    }     
  }

if (total2 >100)  {   // you can change this parameter to fine tune the sensitivity
    if (!check2){         
      Keyboard.press(KEY_CAPS_LOCK);
       Keyboard.press ('g');     
     check2 = !check2;   
    }         
  }
  if (total2 <95) {     
    if (check2){ 
      Keyboard.release ('g'); 
      check2 = !check2; 
    }
  }
}

I get 1-9s on each pin where there is no touch (I am not using foil) and 500-2000 when touched. however when i tried this

#include <CapacitiveSensor.h>

boolean check1 = false;
boolean check2 = false;
boolean check3 = false;
/*
 * CapitiveSense Library Demo Sketch
 * Paul Badger 2008
 * Uses a high value resistor e.g. 10M between send pin and receive pin
 * Resistor effects sensitivity, experiment with values, 50K - 50M. Larger resistor values yield larger sensor values.
 * Receive pin is the sensor pin - try different amounts of foil/metal on this pin
 */


CapacitiveSensor   cs_7_6 = CapacitiveSensor(7,6);  
CapacitiveSensor   cs_2_4 = CapacitiveSensor(2,4);// 10M resistor between pins 4 & 2, pin 2 is sensor pin, add a wire and or foil if desired
 CapacitiveSensor   cs_5_8 = CapacitiveSensor(5,8);      // 10M resistor between pins 4 & 8, pin 8 is sensor pin, add a wire and or foil





void setup()                    
{

Serial.begin (9600);
}
void loop()                    
{
    long start = millis();
    long total1 =  cs_7_6.capacitiveSensor(30);
  long total2 =  cs_2_4.capacitiveSensor(30);
  long total3 =  cs_5_8.capacitiveSensor(30);

    Serial.print(millis() - start);        // check on performance in milliseconds
    Serial.println("\t");                    // tab character for debug windown spacing

               // print sensor output 3

Serial.println (total1);
Serial.println (total2);
Serial.println (total3);
    delay(20);                             // arbitrary delay to limit data to serial port 



  if (total1 >100)  {   // you can change this parameter to fine tune the sensitivity
    if (!check1){         
      Keyboard.press(KEY_CAPS_LOCK);
       Keyboard.press ('f');     
     check1 = !check1;   
    }         
  }
  if (total1 <95) {     
    if (check1){ 
      Keyboard.release ('f'); 
      check1 = !check1;   
    }     
  }

if (total2 >100)  {   // you can change this parameter to fine tune the sensitivity
    if (!check2){         
      Keyboard.press(KEY_CAPS_LOCK);
       Keyboard.press ('g');     
     check2 = !check2;   
    }         
  }
  if (total2 <95) {     
    if (check2){ 
      Keyboard.release ('g'); 
      check2 = !check2; 
    }
  }

    
    }

the serial monitor displays
5868
-2
-2
-2
regularly at intervals of about 1 second ?
why is this , is there some specificity or limit in recive pins I am unaare of or is it something ive done in the code which i’m not seeing. thanks ?