Optimizing mortage payback
 

I have worked out my bond payment on a loan of R700000 over 20 years . I used
PMT, IPMT & PPMT with success. I now want to optimize my bond repayments by
modifying the formula to work out what the effect is going to be after 20
years if: (1) I pay an extra amount into my bond in, for instance, month 6 or
make an immediate first payment (instead of making it at the end of the first
month). (2) Make an additional payment every month or (3) Make 2 weekly
payments (every 14 days) instead of monthly payments.

Thanx
Hannes