If the technicians want credit, they should put it into the contract. If their input into it is a bought-and-sold commodity, which it seems to be, then they’re being paid in lieu of credit. Ghost writers will get paid different amounts depending on if they get to self-attribute or not.
I guess the technician also gets paid regardless of whether the piece is well-received or sells for a high price. So the artist is also taking all of the risk.
