Question 347660
I think the question you're asking is "Is it more likely (probable) that you will operate the plane on 2 engines rather than 4 engines". Because you already stated that a 4 engine plane operates just like a 2 engine plane, so they both operate.
With four engines, the possible {{{2}}} engine failures, there are {{{6}}} configurations with 2 good engines and 2 bad engines from {{{GGBB-BBGG}}}. 
{{{P(2 failed)=6*(0.8)^2(0.2)^2=0.1536}}}
{{{P(0 failed)=1*(0.8)^4(0.2)^0=0.4096}}}
The probability is higher that you will be operating on 4 engines rather than 2.
Surprisingly, P(1 failed)=P(0 failed).