Board Thread:Game Discussion/@comment-81.30.50.6-20181101055138/@comment-37157366-20181102125629

SoLaX 85 wrote: Don't take me seriously, but one funny thought - recommended PR doesn't specify exact upgrades combination - so if you go to 5450400 you'll have PR for Tier 11 and Top speed about 335 kph, so definitely doable and everything according to instructions :)

Well, all 3's is the cheapest way from wikia, but not the only way - what do we know, which way FM wanted us to go? :D Came to my mind as well. Perhaps they are testing the influence of sites like these: how many people upgrade according to recommendations given here or elsewhere?