Actually, yeah! I think on my third playthrough I realized I could go into debt but did it accidentally though! Got nervous since I thought once the day ended, it'd be game over or something, but surprisingly it wasn't! I think that's what made me optimize more, since I prioritized training upgrades while still paying daily quotas! So that's what got me so far.
Also noted on the efficiency upgrade! Didn't know the logic on how the efficiency worked but read an earlier comment of yours on it too so now I'm clear. Thanks :)