Why some relative clause can be reduced and some can not?

I am learning the book named Grammar and Vocabulary for Advanced by Martin Hewings and Simon Haines. I am struggling with the grammar relating to relative clauses. Could you please help me clarify the relative clause in below two sentences?

1. Under the new government proposals, from next year electricity suppliers will have to provide the devices—which have cut power use by up to 6.5% in Canada—to all customers who want them. (Can this sentence be written like this : Under the new government proposals, from next year electricity suppliers will have to provide the devices— cutting power use by up to 6.5% in Canada—to all customers who want them.)
2. However, the monitors, which use microchip technology and a digital play, are intended to be placed in full view as a constant reminder of the electricity that is being used in a house at any given moment. (This sentence can be written like this : However, the monitors, using microchip technology and a digital play, are intended to be placed in full view as a constant reminder of the electricity that is being used in a house at any given moment.)

Could you help me explain why sentence 1 "which have cut" can not be replaced by "cutting"? Is it because of the present perfect used "have cut". For sentence 2, "which use" is reduced by "using".