As a PMT I feel as though I might be able to shed some light on how AC works at the store level. Every store has a certain amount of 'units' on the roof. You have RTUs, and DHUs. RTU stands for Roof Top Unit, and DHU stands for Dehumidification Unit. Stores that have had a Pfresh remodel have an additional DHU over Market, either a Munters, or Seasons 4. Every unit has a corresponding sensor, which come in the way of small, square thermostats, typically mounted on sales floor columns, and in some cases walls.
Every unit has 1, 2, or 3 compressors. They don't all kick on at the same time. Each thermostat has a temperature set point, determined by corporate, and when the zone reaches a certain temperature, the unit will begin to cool. The amount of cooling it will send inside, depends on the temperature of the zone. If the cooling set point is 70, and the zone temp at the thermostat is 71, the unit will run on one compressor as it doesn't need full cooling to get the zone temp satisfied. If that one stage of cooling doesn't cool the area fast enough, the second, or third compressor will kick on to bring the zone temp back below the set point, at which point, cooling will turn off.
At least 2, (sometimes more) units will also allow a certain amount of outside air in at all times, regardless of temp, to maintain appropriate pressure in the store.
DHUs work the same as RTUs, the only differences being they also monitor humidity, and when a sensor reads high humidity in a certain zone, the attached DHU will kick on to take moisture out of the air.
If a certain area of the store feels hotter than others, it could be a few things. It could be that the unit isn't working properly (broken fan belt, dirty filters, electrical issue, alarm), there could be something giving the zone sensor a false reading (fans blowing on it), or the zone could be satisfied, and you personally just don't feel comfortable.
Your PMT has an app on his or her iPad that can be used to see the current status of every zone, set points, discharge air temps, which compressors are running, etc. Its a great tool, and I'm sure the PMT wouldn't mind showing you if you were genuinely curious and asked nicely.