without going into detail, check the top-100 ranking in terms of "highest amount of pp in a game round" if you want a proof that it works.
that ranking actually is biased by USA scenarios, isn't it ? I frankly have no clue how USA scenario works (have only played one round there, and without any real coordination), just that it's completely different than classic and SoE (the one I am very familiar with in terms of PP hunting), and heavily biased in favor of city deliveries, compared to the other 2.
I have never seen anywhere near 1.5M prestige on classic / SoE, except for very special conditions (winter event abuse is the best example).
Claiming you can reproduce USA scenario conditions on a classic seems dubious, and applying the same strategies will simply not work (you don't get the 1000% multipliers).