In the sys that is in the pack that I downloaded at the time, (before the forum crash), there are the categories, so you should have them too, but I've always used Israel with Arimi's skin, her sys, her data and her ux folder.

Category 3 is a category in its own right and does not respond to the rules of the other categories. I also tried to change its lines to have the alert 500 meters before, but it does not work, the alert starts after passing the point and the display of average speeds also starts.

The max_section_time line only affects category 3, so much so that Pongo places it between the lines under "warning" and not among those concerning category 3:

[warning]
is_sound=1
say_camera_distance=1 ;distance to camera
say_camera_speed_limit=1 ;camera speed limit
speedcam_continuous_approach_beep_when_tonal=0

skip_approach_beep=1 ;1=do not repeat "Speed camera."
;speedcam_need_approach_beep_on_section_cameras=1 ;1=reports the distance to the first section camera

max_section_time=240 ;240=average speed zone validity time sec
speedcam_maxdistance_from_road=54

Try to copy all the lines concerning the categories in the plugin.ini of the speedcam.zip file and delete it from the sys, the last files speedcam and sys both Arimi and Pongo are made so. With Total Commander, (free from the Play Store), you can edit them whenever you want and you do not have to delete the save folder.
Rather, if you use one of Arimi's latest speedcams, everything is ready and you have the icons news for you both in the menu and on the route.