4-engine types, symetrical pair, and usually both near high power.
747 outboard engine above 1.3 epr opposite engine to 1.3 (for RR/PW, GE equivalent N1) for balancing, no higher even if you take engine being tested to 1.6 epr. Inboard engines do not require balancing, this is to reduce torsional loads on wings and landing gear.