Only if you assume the 5% of features to be a contiguous block each time. However, if we assume there are, say, 100 features in Word (the real number is likely

Only if you assume the 5% of features to be a contiguous block each time. However, if we assume there are, say, 100 features in Word (the real number is likely much higher), the number of combinations is orders of magnitude higher than 20.