The broker should definitely provide comparable sales to the valuer to have the best chance of a favourable valuation.
All I'm saying is that by purchasing the property at $200k, you've somewhat defined that the property is worth $200k and both the RP Data systems and valuers will rely heavily on your own purchase price to determine the current value of the property.
My own experience is that RP Data is more conservative than Residex, and that Residex is closer to actual sales prices at the moment. It's not always the case, but it's certainly a trend that I see in my limited scope.
Unfortunately the primary valuation company that the majority of lenders use is ValEx. ValEx then subcontracts the jobs to individual jobs to local valuers. ValEx also owns RP Data. Essentially I believe the majority of bank valuations rely on RP Data which I don't believe to be the most consistently accurate reflection of current property values.