Mercedes says it will supply its latest-specification engine to customer teams as soon as it can, having only just got it ready in time for its work team in Italy.
The German car manufacturer has elected to use all its engine development tokens for the race at Monza as part of an early development push of 2016 fuel concepts.
With the new power unit having helped Lewis Hamilton and Nico Rosberg dominate early practice, there appears to be a decent performance step from the updates.
Such a step would be attractive to Mercedes' customer outfits like Williams, Lotus and Force India in their fight for constructors' championship positions.
However, the reason for Mercedes not giving its updated engine to customer teams for the Italian GP was simply down to the tight deadline it had to get two engines ready for its work outfit.
Mercedes F1 engine chief Andy Cowell said: "We would love to be able to supply them [customers], but we need to look at that in the coming weeks to be honest.
"We've been fully focused on getting here. The second engine didn't arrive until lunchtime yesterday.
"It has been one of those great projects where it has been exceptionally tight, with great collaboration with key partners, and we need to reflect after this weekend."
Cowell believes that Mercedes' customer teams are not at too much of a disadvantage running the older specification, because it has proven reliability which means it can be used to the maximum.
"What our customers have got is an impressive specification of power unit, running it absolutely flat out with some nice toys built into it," he said.
"We will look and see what we can do. Of course, we want every Mercedes powered car to do well, and as soon as we can do it, we will do it."
The useage of tokens in the new Mercedes power unit has been split between various components, with improvements to both the internal combustion engine and energy recovery systems.
"It is seven tokens," added Cowell. "We have spent three tokens on the combustion aspect of the engine. The other four tokens I would rather not say where we spent them."