Fixed Rates - In Advance

Hi Guys,

Wondering whether to fix or not and I came across a few banks that have fixed rates with one year payment in advance.

Bank 3 yr 5 yr
ANZ 5.99% 6.84%
Bankwest 7.04% 7.69%
St George 6.79% 7.44%
NAB 6.89% 7.09%
Westpac 6.99% 7.64%

ANZ looks pretty good @ 5.99% for 3 yrs. On a $300K loan this would mean payment of $18K in advance.

This is 1% lower then the normal fixed rate which would mean a saving of $3k pa on a $300K loan. Since you only pay one year in advance, interest on $18K is about $1k so it apears to be saving a total of $2k pa?

What do you think?