Boullier said Austria had provided evidence of that trend, with a resurgent Williams emerging as Mercedes closest challengers over the weekend - and even securing a shock front-row lockout in qualifying - just two Grands Prix after a comparatively lacklustre showing in Monaco.
Red Bull, in contrast, followed up a breakthrough win in Canada with a disappointing weekend on home soil in Austria, with Sebastian Vettel unable to crack the top ten in qualifying and Daniel Ricciardo having to settle for eighth, behind McLaren's Kevin Magnussen, in the race.
Asked in a McLaren teleconference how he judged Williams' form in Spielberg, Boullier said: "Actually it is interesting because it just shows this year that you have a little bit of a strange pecking order in some races, just because of the [track] layout.
"Williams have built a good car; I think they have some weaknesses, but [also] a lot of strengths - on some track layouts. You could see that a twisty track like Monaco they are not in good form, but a track with more chicanes and long straights like Canada and Austria they were.
"I think this year is [also] very dictated by the power unit - the driveability of the car and the power of the engine - and how you deploy your energy. All this is why you have this change in the pecking order and classification over different track layouts."
McLaren have not scored a podium since taking second and third in the Australian season opener, and dropped behind Williams and into sixth in the constructors' standings following last weekend's race in Austria.
Boullier is confident the team turned a corner during the weekend however, saying that the effectiveness of a major upgrade package - the first step of a planned new direction for the team - has boosted belief for the future.
"I do have the confidence that we will have a good car from next year," Boullier said. "We have addressed all the issues internally, and I believe we have made the right changes.
"We have seen already from Austria the first benefits of the changes we have done in terms of organisation, and I think now we are heading in the right way."
McLaren have scored 72 points over the opening eight races this year, and lie 13 behind Williams and 15 behind Force India in the fight for fourth in the constructors' championship. Mercedes lead the way on 301 points, more than double Red Bull in second.