Combines amount of time to replace grain pan on a 550

we have taken out a lot of front grain pans over the years from MF combines. count on at least 10 hours. dismantle machine, take it out, repair it, clean the machine up, put it back in, reassemble machine, and hoping nothing else is wrong while you're in that far. we have gone as far as replacing front grain pan material with plastic. our first unit is out working now - seems to be a winner. my 2 cents, FarmerTom