Yes, this is up to date!! The change to cash in 4.0 was a bug fix. These pages didn’t have that bug in the first place.
BTD6 Income Calculator
Understanding the calculator
The core sources of income are $1 for every pop, and $100+n for completing round n. These make up the round cash column. Due to the high numbers of bloons in later rounds, cash per pop is reduced to $0.5 after round 51, $0.2 after round 61, and $0.1 after 86.
Secondary sources of income can be provided by farms and certain upgrades of other towers, although these are not yet included in this calculator.
Also shown for convenience are the bloon counts for each round, and their Red Bloon Equivalent (RBE) — the total amount of hits (or ‘red bloons’) needed to fully defeat a round.
Freeplay — after round 80 — brings several changes: blimps gain an extra 2% health (and some speed) per round; all non-blimps now have only one child in an effort to reduce lag; and ceramics are replaced by “superceramics” with 60 health, but which give enough cash to make up for having fewer children. Other bloons, such as purple, do not accommodate for this.