The comparison being made is ‘equal or below’ so the condition is evaluated correctly. The issue you are experiencing is that the condition is set to only trigger the Routine when it changes to true, rather than every time it is evaluated. I don’t know why they took this option but I am willing to concede they may have some insight that I don’t, and I can certainly imagine arguments in favour of it.
The description ‘equal or below’ is certainly incomplete.
The above issue could be mitigated if time ranges were ordinary conditions that triggered the automation when they start and end. Again they aren’t for whatever reason. However a number of users choose to use two Routines to toggle the state of a virtual or real binary device such as a switch at the beginning and end of any time range they use in multiple Routines. This device can then be used in trigger conditions instead of the time range.