I am no expert, but I don't think this answer is correct. If the IRA earned money before it was converted, then you _do_ owe federal taxes on that gain. But according to PA:
https://revenue-pa.custhelp.com/app/answers/detail/a_id/274/~/taxability-of-roth-iras-according-to-p...
you do _not_ owe PA taxes on the gain, as long as you really did convert the entire distribution to a Roth.
Put another way, you should not use your basis for federal tax purposes as your basis for PA purposes. I think this all stems from the fact that PA taxes both IRA and Roth IRA contributions when you make them, and doesn't tax distributions from either kind of IRA when you take them in retirement.
I marked mine in the dropdown as a "rollover", because the page I linked above gives the same rules for "roll overs and plan conversions".
