I wouldn't have said it was that simple TBH. APR and REVO may have higher prices due to R&D costs but if a map is not dyno formulated and optimised how can he guarantee it's power output and long term performance? Does it have the same machine code, does it have back count detection program on it; does it use redundant tables or overwrite current ones. and importantly on the RS3, how does he suggest cracking the ECU's as they can't be OBD II flashed?
Anyone can whack up the boost, fuel and ignition timings and max out throttle agression but that doesn't constitute a remap. Some mappers will also provide a guarantee on engine life and damage potentially caused by their map.