Technical director Mike Coughlan insists however that the team will have further updates ready in time for Melbourne.
He said this is a weakness Williams needs to address from last season in order to give drivers Pastor Maldonado and Valtteri Bottas the best chance.
"We didn't deliver on our potential last year," Coughlan explained.
"Pastor's driving towards the end of the season was tremendous; people didn't realise the problems he was carrying in the car.
"Every race [in 2013] we'll have something.
"We're trying to do it in a methodical, engineering-biased way, so obviously your aim is always to make sure you are system checking at the factory such that you are able to take developments straight to the circuit.
"When you have got a new car, you aim for the last couple of days in Barcelona to run in Melbourne specification.
"We will then be in Melbourne with a step forward, which you will see at every other race.
"Malaysia is difficult, but we will take an upgrade to every single circuit."
Coughlan admitted such rapid developments could potentially mean a disparity between Maldonado and Bottas's equipment at times.
"We are absolutely desperate to try and take the same car to every race," he added.
"In some cases, that is not possible but we look after both of our drivers in exactly the same manner.
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