The weight classes used to be round numbers, but they changed them all up or down a couple kilo in 1992 after a doping scandal in order to reset all the records.
And then they did the same thing in 1997, for the same reason.
And then they did the same thing in 2018, for the same reason.
It’s very silly, but I guess it means we get more world record attempts?
No, they have it right. Add-on software means “added to this node/machine”, as in not part of the system image used to configure multiple machines. It’s all very archaic.