Before revision:  However, for small portfolios this approach often leads to zero counts and high count volatility, which makes the estimations unreliable and volatile , and can also produce counter-intuitive prediction patterns  .
After revision:  However, for small portfolios this approach often leads to zero counts and high count volatility, which makes the estimations unreliable and volatile , and can also produce counter-intuitive prediction patterns such as non-parallel/crossing forward PD patterns .