The costs scale to basically unachievable levels after not that many upgrades though, I don't think it would be worth the snow rerolling producers multiple times. Maybe once to farm up loot rating at the start, which is basically mandatory to get very far, but after that a more balanced distribution will get you maybe 1-2 fewer upgrades in each thing without being a hassle and a big drain on snow. Then you have a lot more chances to repeat fights or reroll bad loot / fix your build. By the mid-20s or so producers become irrelevant, you just pump them all into 1 or 2 things so you can maybe afford one more upgrade before the event ends, but one loot reroll can take you from barely scratching an enemy wave to progressing easily again.