This is certainly true. To my perception, putting the calculations aside, the numbers of expansions placed seems to have the biggest impact. In my Beta City, where the city is expanding and I play things much more fast and loose, there have been at least two occasions where I have laid down about 5 expansions together in preparation for a Fellowship Adventure and in the next tournament there has been a very noticeable increase in squad size which made things instantly much more difficult.
Of course the bigger your city gets then the impact of any one extra item makes a smaller and smaller percentage difference in impact.
That is definitely one effect right there
Just to make things a bit more complicated
The formula contains fixed numbers as well, but the variables are AWs, expansions and techs
Imagine a case (completely hypothetical) where including all the fixed numbers gives you the following result:
techs contribute 10
Expansions contribute 100
AWs: contribute 1000
result: 10*100*1000=1 000 000
Adding 1 tech: 11*100*1000 = 1 100 000
Adding 1 expansion: 10*101*1000 = 1 010 000
Adding 1 AW: 10*100*1001 = 1 001 000
Even within the same city it always makes the biggest difference if you increase the smallest contributor, no matter which one the smallest one actually is. The above example could just as well be the reverse, in which case AWs would be the biggest problem, not the smallest. Of course more likely is that the 3 factors are more similar which would then make the difference smaller.
The number of techs is completely dependent on the chapter progress of course, so it is the same for everybody in the same place in the tree. Also expansions are rather closely correlated to chapter progress, although diamonds for premiums are also an influence here as well as the choice of placing gained expansions or not. So those two factors mainly depend on chapter. And that means early in the game adding to those 2 will have a bigger influence
AWs are the factor that depends much more on personal choice. One can have lots in low cahpters (by progressing slowly or not at all) or one can have few in high chapters by deleting detrimental ones.
How does this help? Not at all, no matter what you do, tourneys always get more expensive
Just funny how math works...