The German car manufacturer’s decision to bring its fourth power unit at Spa – the final race where engines could run at a higher oil burn level – prompted a number of conspiracy theories about the motivation of it sacrificing valuable development time.

The wild theories were further fuelled when the FIA clarified that Mercedes would be allowed to keep burning 1.2-litres of oil per 100km with its power unit for the rest of the season, while Ferrari would have to run at a lower 0.9l per 100km for its final engine.

But speaking at the Italian Grand Prix, Mercedes motorsport boss Toto Wolff was adamant that the decision was taken because the team wanted a performance boost from developments introduced in Belgium – and not because of oil burn.

“It was completely blown out of all proportion,” said Wolff about the oil burn saga. “The reason we introduced it early was in order to bring some performance to the track, with the risk of having to do many [more] races until the end of the season than our direct competitors.

“Also you lack time for further development. The longer you wait for the last introduction of engine the more you can probably add the upgrade.”

"These are the reasons we brought it and not in order to extract a performance advantage out of the capability of burning more oil. So if you ask the FIA, you will be quite interested to see what the results are.

Sources have suggested that Mercedes’ engine in Belgium ran below the 0.9l per 100km level during the Belgian GP, so would have complied with the new restriction in place from now anyway.

Although Ferrari was caught by surprise in Belgium about Mercedes’ decision to introduce a new engine in Belgium – having been under the impression that its rival would not do so – the team insists it has no major problem with the matter.

Team principal Maurizio Arrivabene said: “First of all we have no conflict, and I don’t want to comment on this type of thing.

“Mercedes has introduced early one engine, which also has disadvantages during the course of the season as it has no developments left.”

Motorsport.com understands that Ferrari’s final engine could appear at the Malaysian Grand Prix, but only when it has passed reliability tests at Maranello.

There are suggestions that the updates will deliver a good step in performance, but there remain some concerns about longevity.

Arrivabene dismissed suggestions that Ferrari was delaying its introduction in light of the oil burn ruling – which allows it to continue running its engines at the old 1.2 litre per 100km limit.

“First of all, we are not introducing our power unit number four for that reason [oil burn],” he said. “It is nothing to do with that.

“We have a plan at the beginning of the year and we would like to introduce power unit number four at the right time with the right power – this is the answer. It is nothing to do with the oil.”