I am trying to append columns at the end of my data frame to show the quarter IDs during which each customer reached various revenue thresholds, e.g. one column for reaching $50M, another for reaching $75M, another for reaching $100M, and then finally for $150M. However, I noticed that the columns in the middle ($75M and $100M) keep getting overridden by the FOR loops for $150M. What should I add or change to my for loops so that it will not override the previous values?

selected output

df <- read.csv("test.csv", header=TRUE) #load data



### $50M threshold

for (row in 1:nrow(df)) {
  for (i in 6:35) {    #Start in column 6, which is where quarterly rev begins
   
     if (i <= (ncol(df)-4)  &  (df[row,i] + df[row,i+1] + df[row,i+2] + df[row,i+3])>=50000000  ){ #Identify qtr during which an advertiser reached $50M P4Q
   
        qtr_index = (i+4) - 6
        df[row,46] <-sprintf("%dQ%d", floor(qtr_index / 4) + 2016, (qtr_index %% 4) + 1)
      break
    } else {   df[row,46] <- 'N/A'
      
    }
  }
}

### $75M threshold

for (row in 1:nrow(df)) {
  for (i in 6:35) {    #Start in column 6, which is where quarterly rev begins

    if (i <= (ncol(df)-4)  &  (df[row,i] + df[row,i+1] + df[row,i+2] + df[row,i+3])>=75000000){ #Identify qtr during which an advertiser reached $75M P4Q
   
      df[row,47] <- sprintf("%dQ%d", floor(qtr_index / 4) + 2016, (qtr_index %% 4) + 1)
      break
    } else {   df[row,47] <- 'N/A'
    
    }
  }
}


### $100M threshold

for (row in 1:nrow(df)) {
  for (i in 6:35) {    #Start in column 6, which is where quarterly rev begins
 
    if (i <= (ncol(df)-4)  &  (df[row,i] + df[row,i+1] + df[row,i+2] + df[row,i+3])>=100000000){ #Identify qtr during which an advertiser reached $50M P4Q

      df[row,48] <- sprintf("%dQ%d", floor(qtr_index / 4) + 2016, (qtr_index %% 4) + 1)
      break
    } else {   df[row,48] <- 'N/A'
    
    }
  }
}


### $150M threshold

for (row in 1:nrow(df)) {
  for (i in 6:35) {    #Start in column 6, which is where quarterly rev begins

    if (i <= (ncol(df)-4)  &  (df[row,i] + df[row,i+1] + df[row,i+2] + df[row,i+3])>=150000000  ){ #Identify qtr during which an advertiser reached $50M P4Q
   
      df[row,49] <- sprintf("%dQ%d", floor(qtr_index / 4) + 2016, (qtr_index %% 4) + 1)
      break
    } else {   df[row,49] <- 'N/A'
    
    }
  }
}