Going from a 50% tax to none for one year, then 20%, then 30% is pretty significant.
Let's take a three year sample (starting in 2019) without even going over the $40M line:
2019: $246M + $12M tax (30% of $40M)= $258M
2020: $248M + $20M tax (50% of $40M)= $268M
2021: $250M + $20M tax (50% of $40M)= $270M
2022 and 2023 would be similar to 2021 ($270+M x 3= $810M)
Now, make 2021 the reset year:
2021: $210M + no tax= $210
2022: $250M + $8M (20% tax)= $258M
2023: $250M + $12M (30% tax)=$262M
Total: $730M for these 3 years
Maybe $80M might not seem like a lot from our view of Henry's wallet size, but I guess it matters to him.
$80M equals signing a player to $27M x 3 years.
Now, he loses Pablo and Castillo's contracts before these years arrive, and hopefully, no current big contract player becomes dead weight, but even just staying near the $40M line for many years in a row, without re-setting, can become pretty costly.