My issue with it is that there is no real difference in terms of what aerial apparatus can have certain lengths. Looking at Pierce's website you can see that the longest ladder length on a tiller in the exact same as a rear-mount (which can be either single- or tandem-axle).
Even looking at E-One's 137' ladder, it is only available as a rear-mount.
Plus, as noted here
In real life, NFPA designates those 7 types of engines, so they are carried over to here. There are really two types of aerial units: those with on-board water/pump capacity (quint); and those without that capability (platform/ladder/tiller ladder).
LA County, iirc, has both tiller and 'standard' quints in their arsenal. With the 3 options presented in the game (quint, platform, and tiller trailer), any need for an aerial can be met.
I use different graphics for each of my aerials to 'distinguish' them. That is one way to accomplish what you want.
I can't see the devs actually factoring in any type of height for the Skyscraper POI, it isn't necessary.
There is no NFPA designation difference beyond whether the aerial meet the standards to be called a "Quint" or not.