BirchPoint wrote: "I am wondering, though, if it is because I am not using a heavy enough
pan right now so the contact is less than it would be with a good heavy
pan."
A heavier pan of the same diameter only supplies improved heat conduction laterally and greater thermal mass to heat up (lower responsiveness). It is unlikely that contact is an issue because the field from the hob extends out of the cooktop unless "captured" by the inductive pan base. I think the issue is pan shape versus coil shape.
If the shape of the side hobs on the Bosch Benchmark are kept in mind (see image above) then one may see that the degree to which a pan fits a hob or pair of hobs is going to be a measure (probably not linear) of efficiency in coupling the field to the pan base. Thinking about it, I see that this may be a near-fundamental limitation of this type of design; efficiency is traded for convenience, where rectangular pans or griddles that just fit the hob layout are the only shapes where efficiency can be as high as it is for circular pans that fit circular hob coils.
One might extend this thought to the 3-inch coil Freedom unit, where some pan shapes will be more efficient to use than other shapes. In a world of only circular pans, circular hobs of appropriate size (or with tapped coils) will be the most efficient.
On unit thinness: The wonderfulness of advances in electronics surely allows thinner designs with time, but maybe not quite as thin so soon as some units are demonstrating. Otherwise the penalty is reduced maximum power capability due to cooling limitations. This could be a factor in the Bosch and Thermador units requiring that only one hob on a side be operational to use power boost (one pair for the Benchmark), while the over 4 inches thick Electrolux Icon does not impose this limitation.
kas
Q