if i renew the contract now, probably the new contract will commence in Sep 08 and end in Sep 10. In 2010 July, i have to renew the contract in advance again, and the 2nd contract will be Aug 10 ~ Aug 12. In total, i will save the levy of (22+24=)46 months, ie $18400. Here, i have to deduct the levy forfeited, ie 2 x $400 = $800. Net saving = $17600.
on the other hand, if i renew the contract in Oct when my 3rd levy will be due, the new contract will be Nov 08 ~ Nov 10. Similarly, advanced contract renewal in 2010 July and the total levy saving will be (20+24=)44 months, ie $17600.
in both cases, the saving is the same. In regard of the time spent on application, it wont be an issue to have sb look after my bb for a few days.