MM Sparks , Dec 29, 2000; 10:23 a.m.
You've described the ESP function well. It's more akin to matrix metering than spot; the center area measured by the secondary mirror is very large. The OM-2S has a similar exposure system, but the center metered area is small enough to be called "spot" by the manufacturer, but too big for those used to a narrow reading with a true spot meter.
Also, the default "Auto" setting isn't "center weighted averaging" in the way that most other SLR's of the period are. The random pattern on the shutter curtain seems to give the same reflectance across the frame when that method is used (unlike the first OM-2's) and I'm guessing the OTF autoexposure with slower speeds gives a similar reading.