Dates are those discussed for April. Ensure that programmatic exchanges proceed in a timely manner. Out of discussions with Charles at Microsoft. Question of how to verify timeliness. Since you can only do this from another process, you are affected by system scheduling priorities.
Access is then slow.
We found in tests that in-process response times were 12 times faster. The AT user should have the same experience. The other issue is synchronization. Suppose that while the AT is traversing the DOM tree, if the location in memory is deleted, or the element members are distorted, accessing those memory locations could lead to a crash. This is a separate issue.