Hi Lo Pressure Switches Using Latching Relay

I'll set up my scenario first. I am shifting an A518 Dodge auto transmission into overdrive (od) by means of a hobbs type n.o. pressure switch. Power to trans is 12v switched constant and uses negative to signal od shift. When pressure is met at switch it connects to ground and shifts to od. I use a single n.o. switch for this but it shifts in and out right at this speed (psi). I'd like to use two switches, hi and lo, the n.o. switch set to 37psi to shift into od, then have a window of operation until I slow and the pressure drops to 30psi and the second switch, a n.c. switch that is already under pressure and switched open at this time, signals od to turn off, disconnects ground. I was looking at relay diagram #38 Latched On/Off Output Using Two Momentary Negative Pulses - Negative Output (3 relays), except I am sending a constant negative signal, not momentary. Then I looked at #2 Constant to Momentary Output - Negative Input/Negative Output, for a possible fix for the signal. That would be 4 or 5 relays all mounted, would there be a simpler way to do this combining relays? I hope my explanation makes sense. Thank you.