From: Rabbi Moshe Sofer
To: Rabbi Meir Pal
The Chasam Sofer rejects his mechutan's suggestions regarding tipas chalav and the Rema's uncertainty in Siman 92, clarifying that chelev does not permeate from piece to piece without gravy. He defends the Shach's proof in Siman 105 that a piece absorbing a forbidden drop does not become inherently prohibited. He also refutes the Pri Chadash's critique of the Shach by arguing that bishul achar bishul may not constitute a Torah-level violation of basar bechalav, and disagrees with the Pelesi's ruling that steam above the gravy line requires its own calculation of sixty.
Source: Shu"t Chasam Sofer YD §82