Increasing aggressiveness does not come from discretionary income increasing, but instead choosing to invest higher amounts within the same income.
So for example, it could be argued that if a guy had weekly discretionary funds of $100, and he had been investing 33% or $33 into bitcoin each week, then I doubt that his aggressiveness had increased from the mere fact that his weekly discretionary income doubled and he also doubled his investment amount. So if his discretionary income went up to $200 per week and he started to invest $66 per week into bitcoin, it seems to me that his level of aggressiveness is the same - 33%.
You are correct, and I can attest that alot of people usually uses the terms interchangeably, they do mixed being aggressive with more incomes, I see the agreesiveness as a rate not just an amounts, okay if we are to talk about the 33%, you can't actually be agreesiveness if the percentages stays at the same point, but let say you only scale it and the risks still remains at the same level. Agreesiveness is let say for instance now,
BTC 1 has like $100 worth of bitcoin as the discretionary income and decide to invest $33 that's (33%).
BTC 2 has discretionary income of $200 and decide to invest $66 which is same (33%). Then
BTC 3 has $100 and invested $80 that's (80%). So the second one is not more aggressive than the first one while the third one has done most agreesiveness, even if he invested less dollars the second one. But the second one has more incomes, not being aggressive.