The McLaren and Mercedes Formula 1 teams are supporting the push to increase engine allocation to five, but with reservations.
The saga of the push for a change of rules to allow a fifth engine without penalty in 2015 continues to rumble on, and it is apparent that the vote could go either way at next week's Strategy Group meeting.
Today, McLaren's Jonathan Neale made it clear that the team supports the change – as long as there are no strings attached.
Meanwhile, Paddy Lowe of Mercedes insisted that his team would support a move only if the fifth engine was in play to boost Friday practice running, as was originally mooted by those behind it.
Christian Horner told Motorsport.com today that the extra engine should be simply added to the overall allocation for use at any time.
"I don't know whether it will pass, there are conflicting views," said Neale. "There was a certain degree of unanimous agreement amidst the teams in Malaysia. I think that that position has changed from what I can pick up in paddock rumour at the moment.
"What matters most is what case is put to the Strategy Group next week. If it goes to five engines with a thousand strings attached and complex other paraphernalia around it I don't think it will go through.
"We'd obviously benefit from it because we're in a situation as a new entrant to the sport with Honda we would like very much that additional fifth engine, we think that would be fair for us.
"I'm pretty sure Renault would feel the same way. They're investing in the sport, they're a big organisation, it's important for their brand as well that they have some degree of glide path on this."
Lowe noted: "The original reason to agree to it when we were looking at introducing a fifth engine was to improve the amount of running that was done on a Friday. We would agree with it in that context. We'll see what happens in the Strategy Group."
Meanwhile, Williams' Rob Smedley said that he had some reservations about a change during the season: "The World Championship could be compromised. That's what the rule book is for."