George,
For load testing, I'd recommend using LoadComplete. It provides extended support for Flash: you will be able to view and change parameters of application requests and check the response data. As for TestComplete 8.x, it can record traffic and simulate the load, but it does not offer enhanced support for Flash. Also, SmartBear discontinued support for load testing in TestComplete version 9.
Please note that load testing consists in simulating massive workload on the tested server. To do this, both LoadComplete and TestComplete record requests sent from your computer to the server. You can then create load tests that will simulate multiple virtual users, each playing back the recorded requests.
I don't know your application, but often, the zoom in/zoom out operations work on the client part and don't include the data exchange between the Flash app and the server. If your tested app works in a similar manner, then load tests will not help. To simulate and check these zoom in/zoom out operations, you have to use TestComplete and create an ordinary functional test against your Flash app.