Anisha received a 10-year mortgage of $600,000 to purchase a condominium. They negotiated a fixed interest rate of 5% compounded semi-annually for a 6-year term. Their mortgage contract also stated that they could prepay 8% of the original principal every year without an interest penalty. By how much did their amortization period shorten if: 

i) They made a prepayment of $60,000 at the end of the 2nd year? 

ii) They increase the periodic payment by 30% starting from the 3th payment?