Possibility to specify unit conversion multiplier

As Zabbix 4.0 has brings the possibility to prevent unit conversion flexibly it should be optimized a little bit more. In some cases the multiplier for unit conversion is 1000 instead of 1024. So the result value with unit conversion would be wrong.

Therefor I'd like to have the possibility to specify the multiplier. I could imagine a format like this:

[1024]B --> 1024B = 1kB
[1000]W --> 1000W = 1kW