Inverse level sensor?

[H20ENG]

I will be using 3 level sensors.

L1: Topoff, set to "Auto Topoff".

L2: Low sump main pump shutoff, set to "Leakage" and "Invert".

L3: Display tank high level main pump shutoff, set to "Leakage".

I also want to set a timer for L2 and L3 for 20 minutes, latch the Alarm light, with the appropriate Alarm display.

Am I on the right track with my settings?

Then do I need to use the timers for L2 and L3 or do I use programmable logic?

Thanks