The MR2 would shut down engines, when specific weights were reached due to fuel burn; the lighter you got, the less became the requirement for all engines. The loiter capability therefore was improved. But the transit home, at height, was on all engines, as this again, was more fuel efficient.
The MRA4, whilst 4-engined was never envisaged to operate thus. Not because of electrical power requirements, as some suggest, but the drag penalty of a windmilling huge fan engine.
My point is that a 4-engined aeroplane is not necessarily "better" than a 2-engined one.