Hi,
When the Lfo is clock synced to the arpeggiator, when you dial FLO Rate knob, that will set LFO rate to 4, 2, 1, 1/2 or 1/4 of the Arp Tempo.
Either you haven't noticed that already, either I didn't understood your request.
I didn't added more subdivisions, because it would have made it to difficult to find (very narrow) when dialing the Rate knob.