Look at it as an insurance policy I suppose - that $800 should mean you have less problems with the press, although our rotary press doesn't have an external box, all its electrics are internal, and it works fine - the relays and controller modules are mounted on heat sinks. I would question why the manufacturer thinks one of these may be necessary, and negotiate it being included in the price not an additional extra, or go and look at buying another press which is designed to run and work as is, with a manufacturers/suppliers guarantee.