904/999 Starter and Flexplate issue solved

CudaFactHackJob said

So the conclusion is that a 727 flex plate won't work with a 904...um..NO, NOT ALWAYS. General statements like that are all over the web.

Click to expand...

OK I am confused.
I have a mopar performance sfi flexplate and the mini starter.
The flexplate was installed on a 727. Everything fit fine.
Later I changed the trans to a 999, bought a 999 converter from turbo action, same company as the 727 converter.
The same flexplate fit no problem on the 999 and so did the starter.
So is this a problem caused by the converter?