Reply To: drush v'kabel s'char

I believe the way the Achronim say it (quoting the Rambam) is that it’s Kim Lei because the Azhara is Lo Sochlu Al HaDam. So the Chiyuv to pay back money (until then he could just give back the food) comes at the same time as the Lav that brings with it a Chiyuv Misah.