You've got it right.
The top table is the Marathon corrals (including Goofy and Dopey). The bottom table is the Half Marathon corrals. The 2:45 HM POT race equivalent corral for the HM is Corral E, which I put an estimated cutoff at 1:14:46 for a converted 10k. Corral D would be a 1:07:59 necessary 10k. Thus, your wife's time of 1:13:36 is most likely in Corral E (or the last POT submittable corral).
As a different example, let's say someone signed up for the Dopey challenge. They have possible POT times of a 10 mile time of 1:23:00, a HM time of 1:58:00, and a M time of 4:45:00. They would use the top table to estimate the corral positions based on converting different race distances to a marathon equivalent.
-Submit the M time of 4:45:00 and the person is likely to end up in Corral D. To move to Corral C, they would need a 4:30:00 M or less. See yellow column "Marathon".
-Submit the HM time of 1:58:00 and the person is likely to end up in Corral C. To move to Corral B, they would need a 1:53:32 HM or less. See blue column "HM -> runDisney?"
-Submit the 10 mile time of 1:23:00 and the person is likely to end up in Corral B. To move to Corral A, they would need a 1:17:44 10 miler or less. See purple column "10 mile -> runDisney?"
The times shown in each box corresponding with each Corral letter represent the cutoff (or necessary time) to gain access to that specific corral. Since a 1:23:00 10 miler is less than 1:24:48, but greater than 1:17:44, then the 10 miler POT puts that runner in Corral B.
Remember these are not definitive but a very reasonable guess. As always, if runDisney changes the corralling system then this above example could easily be different. Based on the registration though, the one thing I am fairly confident of is the last three corrals being as displayed above based on choosing a non-POT corral and estimated finish.