The evaporator sensor/ecu/trinary switch controls the relay Frank, the cycling is completely normal and indicative of a system working efficiently. The 'auto' function is working with input from the other sensors so it is in effect 'anticipating' the temperature changes and bringing in the compressor control ECU. I too find myself 'fiddling' with the slider until I concede the 'AUTO' is just a little better at keeping the temp right than I am.
Other things will effect the compressor cycle for instance, the VC on the cooling fan, road speed, cleanliness of the condenser/radiator core/outside temperature and so forth. My use of an electric fan and trinary switch control of the same has made my system very effective as per my thread on MUD. The newer more modern systems are more 'clever' and efficient at compressor/temperature control but, it seems you are more or less getting the best from 'our' antiquated systems, if you want to keep the VC fan then consider the Toyota optional additional electric fan that sits in front of the condenser.
regards
Dave