I just found out that many electricity providers in VIC has reduced their plans from 01/01/2021. So, it is better to compare your current one with others and there may be a better deal for you. I have found out many cheaper ones and switched to the cheapest one.
VIC Energy Compare is your friend : https://compare.energy.vic.gov.au/
Anyway, I always use Excel and verify it further by checking last year's usage data.
Thanks for the reminder op. My current Tango Energy rates are about 4% higher than currently promoted. Calling them now.