Hi mmm!
Congratulations - 20kg is an incredible amount to shift! Sorry to hear of your sad loss, as chezza said, we have been through similar losses, but are both finding that a fitness focus is a great way forward.
My scales are Kmart ones! They do the job - I think as long as you're using the same ones, and weighing yourself at the same time of day, you should be OK.

Hey chezzy-pops, got a hot dress for the wedding?