Automatic CPU frequency stepping was introduced in 6.48 too. But I remember it got limited to 716MHz, I don’t have any devices with 6.48.x to test again, I’m still on 6.46.7 on most of them 
What’s new in 6.48 (2020-Dec-22 11:20):
*) arm - added support for automatic CPU frequency stepping for IPQ4018/IPQ4019 devices;
Apparently I’ve reported this on 7.1beta2 too:
http://forum.mikrotik.com/t/v7-1beta2-development-is-released/142356/156
Let’s not kill the hardware prematurely, shall we?