How is the flex plate balanced?

[nielsmobers]

I've bought a new flex plate on recommendation of an USA garage because the installed flex plate has a balance problem. The new flex plate looks like a hobby project, the gear wheel and the balance weight are welded on and there is no sign of any balance tuning. Is the flex plate made by a computer welding machine and is that the reason it isn't 'balance tuned'?? It does not look like a precision component. An other question: is it necessary to center the flex plate or is it only possible to fix it one way.

Niels