Kavod HaRav, The source you mention from Rabbi Yisrael Isserlein, is NOT the Terumas HaDeshen, but rather Pischei Teshuvah, Orach Chaim §156, by the 19th century Lithuanian Posek, Rabbi Yisrael Isser Isserlein. I'm only mentioning this because otherwise it would be quite difficult to find the source inside.

<p class="MsoNormal"><span style="font-size: 12.0pt; font-family: 'Times New Roman',serif; mso-fareast-font-family: 'Times New Roman';">Thank you so much for pointing&nbsp;out this very obvious error! It is very greatly appreciated and was an absolute mistake on my part. May we always be in communication with each other <span dir="RTL" lang="HE">להגדיל תורה ולהאדירה</span>.&nbsp;</span></p> <p class="MsoNormal"><span style="font-size: 12.0pt; font-family: 'Times New Roman',serif; mso-fareast-font-family: 'Times New Roman';">All the very best,&nbsp;</span></p> <p class="MsoNormal"><span style="font-size: 12.0pt; font-family: 'Times New Roman',serif; mso-fareast-font-family: 'Times New Roman';">Shay&nbsp; &nbsp;</span></p>