It's more like this:
Assume you have a wanted level of 25. With your heat capped at 3x the wanted level, you can have a maximum heat of 75. When you have between 1 and 29 heat (approximately), it takes longer to lose OR gain your heat. Between 30 and 41, it takes little time for your heat to changes. Between 42 and 75, it then takes longer to lose or gain heat.
Theoretically it would take the same amount of time to lose your heat. It just places more emphasis on:
- More effective escape mechanisms when a criminal is being cracked down on by the police with low heat.
- Giving police a slightly longer period to pursue a criminal before they lose their heat.
My original implementation would have looked like this:

Which would emphasize:
- Criminals making a swift and speedy escape, making sure not to attract unwanted attention in the lower heat stages, while making it take longer to reach the maximum to avoid undesirably long chases.
- Police exerting more effort to stay on the tail of a wanted criminal, especially in the lower heat stages.
And just to compare, this is how heat works now:
