It looks like Trenitalia have increased the price of Frecce reservations from €10 to €13. ÖBB now mention €13 for most Frecce, although some (still?) appear for €10.
Italiarail still show €10, but if you then you continue to book, it will change to €13. Seat61 has also changed the price to €13 on most of the pages, so I guess it has really changed.
Intercity reservations in Italy seem to remain at €3.
EC reservations from/to Switzerland seem to remain at €11/€13.