A loan modification typically requires no printing, and documents are shipped directly to your door. You go out, verify ID, get your journal signed, have the borrower sign 4 or 5 docs, usually complete two notarial acts (sometimes 3), put the docs in a return envelope included in the doc package, and drop it in a box. Update your journal. Low cost, minimal time. Yes, $40 to $50 is standard.
An example of a signing that involves loan documents (refi or buyer), standard for my state: Print 300+ pages (2 copies of the package - one to leave with the borrower and one to sign and return); prepare the docs and journal for signing. Travel to borrower, verify ID, get journal signed, monitor signing of 35+ documents (under oath for jurats), double-check at table that all signatures and dates are correct. Return to office, fax back if required, then package documents and ship out.
The time and cost involved in a loan signing is significantly greater than in a loan modification, and one would hope the fee offered would reflect the greater level of responsibility.