[VAC] Oil in my L.P. line?

[Scott McVetty <rubco@xxxxxxxxxxxxx>]

Hello 
   I stopped by my local R.V. service shop today to inquire about the lower
pressure I've had in my gas lines lately.
   I offered to bring him my 4 month old regulater for inspection, but he told
me he couldn't test it off my system. He also told me that it was most likely
an "oil build-up" in the line, and offered to blow it out with his compressor
for $75 up front and $75/hour labour.
   Does this seem realistic to anyone else?
   Could I rig up a solution with my buddies compressor?
   Am I getting hosed with the price?

                                                     Thanks in advance
                                                         Scott