Kubica and team-mate George Russell amassed only 88 laps – substantially down on its opponents – as Williams finished at the rear of the field.
But this week Williams has already racked up 249 laps – putting it fifth on the rankings – only 38 shy of leaders Renault.
“Unfortunately we are running a bit late with our test programme as last week we had an issue,” he said.
“It’s a bit of a mixed feeling, because, from one point, it has been a positive that we did a lot of laps.
“From the other side, it’s also true that we are missing not a lot of time that we are going to race.
“We are not in the position we would like to be, especially from my side, from an engineering point of view also.
“We are doing a lot of gathering data, checking different things and not really working on the car.
“I hope on the next two days, I hope we will have time to start playing with the car and see how the car reacts to different things.”
Kubica added that Williams just has to take the “maximum” from the remaining available time through Thursday and Friday’s running.
“It’s been a good day, especially if you take into consideration what we went through last week with technical issues, with no car, with some delays, and in the end,” he said.
“This should be our day last week, the first day of running.
“But unfortunately we can’t gain the time we lost so we have to make sure we make the maximum from what we have.”
Russell will carry out running in the FW42 on Thursday.
Source: Motorsport Week