int pinLED = 13;

byte LED;
byte oldStatusLED;
boolean statusLED_On = true;
byte status;
unsigned long lastBlink = 0;
unsigned long intervalBlink;

// declare a structure of pin and interval
struct DipSwitch
{
  const uint8_t pin;        // the gpio
  const uint16_t interval;  // the interval in seconds
};

// make an array of dipswitches and initialize the values
DipSwitch dipSwitch[]
{
  {8, 2}, // calculate (2 * factor) = 20000
  {12, 4}, // calculate (4 * factor) = 40000
};

// calculate the setted interval
uint32_t getInterval()
{
  const uint16_t factor = 1000; // millis for seconds
  uint32_t interval = 0;

  for (auto &i : dipSwitch)
  {
    if (digitalRead(i.pin) == LOW) interval += i.interval;
  }
  return interval * factor;
}

void setup()
{
  Serial.begin(115200);
  for (auto &i : dipSwitch)
  {
    pinMode(i.pin, INPUT_PULLUP);
    pinMode(pinLED, OUTPUT);
  }
}

void loop()
{
  //get interval
  intervalBlink = getInterval();
  //blink the led
  if (millis() - lastBlink >= intervalBlink) {
    lastBlink = millis();
    digitalWrite(pinLED, !digitalRead(pinLED));
  }
}