Speaking of AC units, our current thermostat has a differential of 1°, and there's no way to change it. It came with the house, and is kind of junky. Is that typical though? The thing seems to cycle every 5-10 minutes at night. I'd assume with other units, you would be able to set that, or they would have the delay your old unit had, Passed. I was able to find the instructions online, which is how I got my information.
I don't know if 1° hysteresis is normal, or how often the AC should kick on. I never notice. I'm not aware of a way to change, but I'd guess with these fancy electronic thermostats there's a way. Not very hard to change thermostats, so maybe just get a new one. That one from Nest is pretty sweet.
My new unit has 2 compressors (big and small) and about 10 speeds on the air handler, so I think when it kicks on for small temperature changes, it's the small compressor, and you can't even feel the air flowing out the ceiling vents at low speed.