Lewis Hamilton says "There is not a huge difference."
McLaren is because Mercedes was offering a lighter deal in terms of the team's non-driving expectations.
"We still have sponsors, sponsors' appearances and filming days," he told reporters at the final Barcelona test on Thursday.
"There is not a huge difference. (Just that) the focus is on the driver, the driver's performance, the driver being ready for the job at hand.
"That's one thing I'm noticing is a little bit better here," added Hamilton.