Rob Smedley has revealed that F1's decision to push forward the start of the 2016 season will be "more costly" for the F1 teams.
Initially Formula 1 had planned for a later than usual start to the season with the Australian Grand Prix taking place in April.
However, that was later revised to March 20th meaning pre-season testing has also had to be bumped up.
And that, Smedley, is costing the teams.
"It has an impact, there's no doubt about that," the Williams performance chief told Autosport.
"But we have rejigged all the plans now, we have sat down and looked at an operational plan to get us from this point to the first day of the first test.
"That plan was already done and under way and we've had to redo that. It's just going to be more costly for us.
"It won't make a difference to when everyone sees the new car or in what state the new car runs or how it runs in the first test or how it runs in Australia – those plans won't change."
The Brit went on to explain that as a result of the early tests, Williams will have to subcontract out some of the work while they may arrive at Barcelona with a shortage of parts.
"It'll just be more costly to us and all the other teams because you have to rejig your manufacturing plans because you don't want to change your design plans," he said.
"You would subcontract some of it out, especially the composites and bodywork.
"We will probably be a little bit shorter on parts in the first test then we would like to be but that is just something we have to live with.
"You can't magic parts out of the air. We will probably get to first few days with less than operational quantities.
"The change has big ramifications."