I’d agree with your analysis, but soil type is not an absolute thing. Here in Texas, we have access (via agriculture extension service or university web sites) to the actual AWC (Available Water Capacity) from topographical studies and maps. Loam in Michigan is 'way different than loam in Texas!
As I understand it (perhaps paraphrasing you), AWC is the amount of water that can be retained in the “average” arable surface profile of your area. It’s measured in inches of water per inch of the profile. Your table labels it “Field Capacity”. Texas A&M says 'TX073 Sacul fine sandy loam to underlying clay/clay loam @10" ’ with AWC values with local variation from 0.16 - 0.20 where I live. (Yes, this would be “arid” to a lot of Rachio users!)
AWS (Available Water Supply) - what Rachio calls “Available Water” is the available reservoir of water within the root zone, where it matters. Generally, it’s determined by multiplying AWC by the depth of your root zone. For home irrigation it’s measured in inches of water - the irrigation requirement to refill it. “Allowed Depletion” is a percentage of the FULL capacity of the root zone that can be removed by all factors before water MUST be added to recharge the root profile. To confuse things a bit, Rachio’s “Soil Moisture” shown for zones is the percentage remaining of that portion of the zone profile allowed to be depleted (100% is full, 0% is at or below Allowed Depletion). Tap “Soil Moisture” to see this. The higher you set Allowed Depletion, the less frequently Rachio needs to water and the tougher its flora needs to be. 50% is Rachio’s default - seems a pretty good number. It turns out, as the wilting point and residual columns of your chart illustrate, plants wilt - and then die - as you drop into the bottom half of the soil profile’s capacity.
I’d say, in answer to your second question, no - there’s little benefit from dropping too deep into that bottom half of the profile’s capacity - Rachio will not water less overall to do so, it will just delay filling it. Your “wilting point” data says that all soil types get risky close to 50%.