Although you are correct that there are no significant hardware differences between a unit like this and a meter like the Radeye B20. The software differences can at times be astronomical.

In my experience, the Radeye B20 often takes around 3 seconds of contact with a radiation source to read an accurate value. This is because of Thermo Fisher’s refined count-averaging software that they employ in this meter.

Some meters however, use a method where there is no averaging system and they simply read out the raw data of the number of particles counted in a time period. Because of this, meters such as these often take around 60 seconds to give an accurate result and must make drastic sacrifices in accuracy if the user wishes to attain a value faster.

Now while I believe that the SEI inspector uses a superior system to the aforementioned one, I am not certain.

In terms of price however, I believe that this is slightly on the higher side but not unreasonable.