I would caution against adding the neutralizing baking soda while the frame is in the OA bath. When I did this with a Raleigh Pro the paint was bleached in a marbleized pattern where I sprinkled in the soda, something about the reaction that occurs at the time that the soda meets the acid.
Now I remove the frame from the bath and add the Baking soda. Once the reaction subsides I re-immerse the frame in the bath to neutralize the acid solution that remains inside the fame tubes.
Brent