The leap is for 10 years. When they mentioned "After 20 years", SBS meant the time span of the whole serial. That is including the coming leap, KS has spaned 20 years. That is why Jai is only 60 and Bani is 40 cos the current leap is 10 years.
pri edit ur topic as ur munna is only going to be 63 but really must be in bad health that's why using stick at 63 and this could be either due to excessive shots, diabetes, hypertension, so don't ask for more shots or scores from him as that may land him in grave